Chapter IX: Front Matter (9)

Of the authorship of _Chronicles_ we know only what can be determined by internal evidence. The style of the language, and also the position of the book in the Jewish Canon, stamp the book as one of the latest in the Old Testament, but lead to no exact determination of the date.[1] In 1 Chron. xxix. 7, which refers to the time of David, a sum of money is reckoned by _darics_, which certainly implies that the author wrote after this Persian coin had been long current in Judaea. In 1 Chron. iii. 19 sqq. the descendants of Zerubbabel seem to be reckoned to six generations (the Septuagint reads it so as to give as many as eleven generations), and this agrees with the suggestion that Hattush (verse 22), who belongs to the fourth generation from Zerubbabel, was a contemporary of Ezra (Ezra viii. 2). Thus the compiler lived at least two generations after Ezra. With this it accords that in Nehemiah five generations of high priests are enumerated from Joshua (xii. 10 seq.), and that the last name is that of Jaddua, who, according to Josephus, was a contemporary of Alexander the Great (333 B.C.). That the compiler wrote after the fall of the Persian monarchy has been argued by Ewald and others from the use of the title king of Persia (2 Chron. xxxvi. 23), and from the reference made in Neh. xii. 22 to Darius III. (336-332 B.C.). A date some time after 332 B.C. is now accepted by most modern critics. See further EZRA AND NEHEMIAH.

Character of the work.

What seems to be certain and important for a right estimate of the book is that the writer lived a considerable time after Ezra, and stood entirely under the influence of the religious institutions of the new theocracy. This standpoint determined the nature of his interest in the early history of his people. The true importance of Hebrew history had always centred in the fact that this petty nation was the people of Yahweh, the spiritual God. The tragic interest which distinguishes the annals of Israel from the forgotten history of Moab or Damascus lies wholly in that long contest which finally vindicated the reality of spiritual things and the supremacy of Yahweh's purpose, in the political ruin of the nation which was the faithless depository of these sacred truths. After the return from the Exile it was impossible to write the history of Israel's fortunes otherwise than in a spirit of religious pragmatism. But within the limits of the religious conception of the plan and purpose of the Hebrew history more than one point of view might be taken up. The book of Kings looks upon the history in the spirit of the prophets--in that spirit which is still echoed by Zech. i. 5 seq., but which had become extinct before the Chronicler wrote. The New Jerusalem of Ezra was organized as a municipality and a church, not as a nation. The centre of religious life was no longer the living prophetic word but the ordinances of the Pentateuch and the liturgical service of the sanctuary. The religious vocation of Israel was no longer national but ecclesiastical or municipal, and the historical continuity of the nation was vividly realized only within the walls of Jerusalem and the courts of the Temple, in the solemn assembly and stately ceremonial of a feast day. These influences naturally operated most strongly on those who were officially attached to the sanctuary. To a Levite, even more than to other Jews, the history of Israel meant above all things the history of Jerusalem, of the Temple, and of the Temple ordinances. Now the writer of Chronicles betrays on every page his essentially Levitical habit of mind. It even seems possible from a close attention to his descriptions of sacred ordinances to conclude that his special interests are those of a common Levite rather than of a priest, and that of all Levitical functions he is most partial to those of the singers, a member of whose guild he may have been. From the standpoint of the post-exilic age, the older delineation of the history of Israel, especially in the books of Samuel and Kings, could not but appear to be deficient in some directions, while in other respects its narrative seemed superfluous or open to misunderstanding, as for example by recording, and that without condemnation, things inconsistent with the later, post-exilic law. The history of the ordinances of worship holds a very small place in the older record. Jerusalem and the Temple have not that central place in the book of Kings which they occupied in the minds of the Jewish community after the Exile. Large sections of the old history are devoted to the religion and politics of the ten tribes, which are altogether unintelligible and uninteresting when measured by a strictly Levitical standard; and in general the whole problems and struggles of the prophetic period turn on points which had ceased to be cardinal in the life of the New Jerusalem, which was no longer called to decide between the claims of the Word of Yahweh and the exigencies of political affairs and social customs, and which could not comprehend that men absorbed in deeper spiritual contests had no leisure for the niceties of Levitical legislation. Thus there seemed to be room for a new history, which should confine itself to matters still interesting to the theocracy of Zion, keeping Jerusalem and the Temple in the foreground, and developing the divine pragmatism of the history, not so much with reference to the prophetic word as to the fixed legislation of the Pentateuch, so that the whole narrative might be made to teach that the glory of Israel lies in the observance of the divine law and ritual.

Contents.

For the sake of systematic completeness the book begins with Adam, as is the custom with later Oriental writers. But there was nothing to add to the Pentateuch, and the period from Moses to David contained little that served the purpose. The early history is therefore contracted into a series of tribal and priestly genealogies, which were doubtless by no means the least interesting part of the work at a time when every Israelite was concerned to prove the purity of his Hebrew descent (cp. Ezra ii. 59, 62). Commencing abruptly (after some Benjamite genealogies) with the death of Saul, the history becomes fuller and runs parallel with the books of Samuel and Kings. The limitations of the compiler's interest in past times appear in the omission, among other particulars, of David's reign in Hebron, of the disorders in his family and the revolt of Absalom, of the circumstances of Solomon's accession, and of many details as to the wisdom and splendour of that sovereign, as well as of his fall into idolatry. In the later history the ten tribes are quite neglected ("Yahweh is not with Israel," 2 Chron. xxv. 7), and political affairs in Judah receive attention, not in proportion to their intrinsic importance, but according as they serve to exemplify God's help to the obedient and His chastisement of the rebellious. That the compiler is always unwilling to speak of the misfortunes of good rulers is not necessarily to be ascribed to a deliberate suppression of truth, but shows that the book was throughout composed not in purely historical interests, but with a view to inculcating a single practical lesson. The more important additions to the older narrative consist partly of statistical lists (1 Chron. xii.), partly of full details on points connected with the history of the sanctuary and the great feasts or the archaeology of the Levitical ministry (1 Chron. xiii., xv., xvi., xxii.-xxix.; 2 Chron. xxix.-xxxi., &c.), and partly of narratives of victories and defeats, of sins and punishments, of obedience and its reward, which could be made to point a plain religious lesson in favour of faithful observance of the law (2 Chron. xiii., xiv. 9 sqq.; xx., xxi. 11 sqq., &c.). The minor variations of _Chronicles_ from the books of Samuel and Kings are analogous in principle to the larger additions and omissions, so that the whole work has a consistent and well-marked character, presenting the history in quite a different perspective from that of the old narrative.

Sources.

The chronicler makes frequent reference to earlier histories which he cites by a great variety of names. That the names "Book of the Kings of Israel and Judah," "Book of the Kings of Judah and Israel," "Book of the Kings of Israel," and "Affairs of the Kings of Israel" (2 Chron. xxxiii. 18), refer to a single work is not disputed. Under one or other title this book is cited some ten times. Whether it is identical with the Midrash[2] of the book of Kings (2 Chron. xxiv. 27) is not certain. That the work so often cited is not the Biblical book of the same name is manifest from what is said of its contents. It must have been quite an extensive work, for among other things it contained genealogical statistics (1 Chron. ix. 1), and it incorporated certain older prophetic writings--in particular, the _deb[=a]r[=i]m_ ("words" or "history") of Jehu the son of Hanani (2 Chron. xx. 34) and possibly the vision of Isaiah (2 Chron. xxxii. 32). Where the chronicler does not cite this comprehensive work at the close of a king's reign he generally refers to some special authority which bears the name of a prophet or seer (2 Chron. ix. 29; xii. 15, &c.). But the book of the Kings and a special prophetic writing are not cited for the same reign. It is therefore probable that in other cases than those of Isaiah and Jehu the writings of, or rather, about the prophets which are cited in _Chronicles_ were known only as parts of the great "book of the Kings." Even the genealogical lists may have been derived from that work (1 Chron. ix. 1), though for these other materials may have been accessible.

The two chief sources of the canonical book of Kings were entitled _Annals_ ("events of the times") _of the Kings of Israel_ and _Judah_ respectively (see KINGS). That the lost source of the _Chronicles_ was not independent of these works appears probable both from the nature of the case and from the close and often verbal parallelism between many sections of the two Biblical narratives. But while the canonical book of Kings refers to separate sources for the northern and southern kingdoms, the source of _Chronicles_ was a history of the two kingdoms combined, and so, no doubt, was a more recent work which in great measure was doubtless based upon older annals. Yet it contained also matter not derived from these works, for it is pretty clear from 2 Kings xxi. 17 that the _Annals of the Kings of Judah_ gave no account of Manasseh's repentance, which, according to 2 Chron. xxxiii. 18, 19, was narrated in the great book of the Kings of Israel. It was the opinion of Bertheau, Keil and others, that the parallelisms of _Chronicles_ with _Samuel_ and _Kings_ are sufficiently explained by the ultimate common source from which both narratives drew. But most critics hold that the chronicler also drew directly from the canonical books of Samuel and Kings as he apparently did from the Pentateuch. This opinion is not improbable, as the earlier books of the Old Testament cannot have been unknown in his age; and the critical analysis of the canonical book of Kings is advanced enough to enable us to say that in some of the parallel passages the chronicler uses words which were not written in the annals but by one of the compilers of _Kings_ himself. In particular, _Chronicles_ agrees with _Kings_ in those short notes of the moral character of individual monarchs which can hardly be ascribed to an earlier hand than that of the redactor of the latter book.[3]

Treatment of history.

For the criticism of the book it is important to institute a careful comparison of Chronicles with the parallel narratives in _Samuel_-_Kings_.[4] It is found that in the cases where _Chronicles_ directly contradicts the earlier books there are few in which an impartial historical judgment will decide in favour of the later account, and in any point that touches difference of usage between its time and that of the old monarchy it is of no authority. The characteristic feature of the post-exilic age was the re-shaping of older tradition in the interest of parenetic and practical purposes, and for this object a certain freedom of literary form was always allowed to ancient historians. The typical speeches in Chronicles are of little value for the periods to which they relate, and where they are inconsistent with the evidence from earlier writings or contain inherent improbabilities are scarcely of historical worth. According to the ordinary laws of research, the book, being written at a time long posterior to the events it records, can have only a secondary value, although that is no reason why here and there valuable material should not have been preserved. But the general picture which it gives of life under the old monarchy cannot have the same value for us as the records of the book of Kings. On the other hand, it is of distinct value for the history of its time, and presents a clear picture of the spirit of the age. The "ecclesiastical chronicle of Jerusalem," as Reuss has aptly called it, represents the culminating point (as far as the O.T. Canon is concerned) of that theory of which examples recur in Judges, Samuel and Kings, and this treatment of history in accordance with religious or ethical doctrines finds its continuation in the didactic aims which characterize the later non-canonical writings (cf. JUBILEES; MIDRASH).

The most prominent examples of disagreement with earlier sources may
be briefly noticed. Thus, it would appear that the book has confused
Jehoiakim and Jehoiachin (2 Chron. xxxvi. 5-8) and has statements
which directly conflict with 2 Sam. xxi. 19 (1 Chron. xx. 5; see
GOLIATH), and 1 Kings ix. 10 seq. (2 Chron. viii. 2); it has changed
Hezekiah's submission (2 Kings xviii.) into a brave resistance (2
Chron. xxxii. 1-8) and ignored the humiliating payment of tribute by
this king and by Joash (2 Kings xii. 18; 2 Chron. xxiv. 23 sqq.).[5]
That Satan, and not Yahweh incited David to number Israel (1 Chron.
xxi.; 2 Sam. xxiv. 1) accords with later theological development.

A particular tendency to arrange history according to a mechanical
rule appears in the constant endeavour to show that recompense and
retribution followed immediately on good or bad conduct, and
especially on obedience or disobedience to prophetic advice. Thus, the
invasion of Shishak (see REHOBOAM) becomes a typical romance (2 Chron.
xii.); the illness of Asa is preceded by a denunciation for relying
upon Syria, and the chronology is changed to bring the fault near the
punishment (2 Chron. xv. seq.). The ships which Jehoshaphat made were
wrecked at Ezion-geber because he had allied himself with Ahaziah of
Israel despite prophetic warning (2 Chron. xx. 35 sqq.; 1 Kings xxii.
48; cf. similarly the addition in 2 Chron. xix. 1-3), and the later
writer supposes that the "Tarshish ships" (large vessels such as were
used in trading with Spain--cf. "Indiamen") built in the Red Sea were
intended for the Mediterranean trade (cf. 2 Chron. ix. 21 with 1 Kings
x. 22). The Edomite revolt under Jehoram of Judah becomes the penalty
for the king's apostasy (2 Chron. xxi. 10-20; 2 Kings viii. 22),
Ahaziah was slain because of his friendship with Jehoram (2 Chron.
xxii. 7). The Aramaean invasion in the time of Joash of Judah was a
punishment for the murder of Jehoiada's son (2 Chron. xxiv.; 2 Kings
xii.). Amaziah, after defeating Edom (2 Chron. xxv., esp. verses
19-21; see 2 Kings xiv. 10 seq.), worshipped strange gods, for which
he was defeated by Joash of Israel, and subsequently met with his
death (2 Chron. xxv. 27; 2 Kings xiv. 19). Uzziah's leprosy is
attributed to a ritual fault (2 Chron. xxvi. 4 seq., 16 sqq.; cf. 2
Kings xv. 3-5; see UZZIAH). The defeat and death of the good king
Josiah came through disobedience to the Divine will (2 Chron. xxxv. 21
seq.; see 2 Kings xxiii. 26 sqq.).

In addition to such supplementary information, another tendency of the
chronicler is the alteration of narratives that do not agree with the
later doctrines of the uniformity of religious institutions before and
after the exile. Thus, the reformation of Josiah has been thrust back
from his eighteenth to his twelfth year (when he was nineteen years
old) apparently because it was felt that so good a king would not have
tolerated the abuses of the land for so long a period,[6] but the
result of this is to leave an interval of ten years between his
conversion and the subsequent act of repentance (2 Chron. xxxiv. 3-6;
2 Kings xxii. seq.). References to Judaean idolatry are omitted (1
Kings xiv. 22-24; see 2 Chron. xii. 14; 2 Kings xviii. 4; 2 Chron.
xxxi. 1) or abbreviated (2 Kings xxiii. 1-20; 2 Chron. xxxiv. 29-33);
and if the earlier detailed accounts of Judaean heathenism were
repulsive, so the tragic account of the fate of Jerusalem was a
painful subject upon which the chronicler's age did not care to dwell
(contrast 2 Kings xxiv. 8-xxv. with the brief 2 Chron. xxxvi. 9-21).
At an age when the high places were regarded as idolatrous it was
considered only natural that the good kings should not have tolerated
them. So 2 Chron. xiv. 5, xvii. 6 (from unknown sources) contradict 1
Kings xv. 14, xxii. 43 (that Asa and Jehoshaphat did _not_ demolish
the high places), whereas xv. 16-18, xx. 31-34, are quoted from the
book of Kings and give the older view. The example is an illustration
of the simple methods of early compilers. Further, it is assumed that
the high place at Gibeon was a legitimate sanctuary (2 Chron. i. 3-6;
1 Kings iii. 2-4; 1 Chron. xxi. 28-30; 2 Sam. xxiv.); that the ark was
borne not by priests (1 Kings viii. 3) but by Levites (2 Chron. v. 4),
in accordance with post-exilic usage; and that the Levites, and not
the foreign bodyguard of the temple, helped to place Joash on the
throne (2 Chron. xxiii.).[7] Conversely 1 Chron. xv. 12 seq. explains
xiii. 10 (2 Sam. vi. 7) on the view that Uzza was not a Levite, hence
the catastrophe.

Throughout it is assumed that the Levitical organization had been in
existence from the days of David, to whom its foundation is ascribed.
In connexion with the installation of the ark considerable space is
devoted to the arrangements for the maintenance of the temple-service,
upon which the earlier books are silent, and elaborate notices of the
part played by the Levites and singers give expression to a view of
the history of the monarchy which the book of Kings does not share.[8]
Along with the exceptional interest taken in Levitical and priestly
lists should be noticed the characteristic preference for genealogies.
Particular prominence is given to the tribe and kings of Judah (1
Chron. ii.-iv.), and to the priests and Levites (1 Chron. vi., xv.
sq., xxiii.-xxv.; with ix. 1-34 cf. Neh. xi.). The historical value of
these lists is very unequal; a careful study of the names often proves
the lateness of the source, although an appreciation of the principles
of genealogies sometimes reveals important historical information; see
CALEB, GENEALOGY, JUDAH. But the Levitical system as it appears in its
most complete form in Chronicles is the result of the development of
earlier schemes, of which some traces are still preserved in
_Chronicles_ itself and in _Ezra-Nehemiah_. (See further LEVITES.)

The tendency of numbers to grow is one which must always be kept in
view--cf. 1 Chron. xviii. 4, xix. 18 (2 Sam. viii. 4 [but see LXX.],
x. 18), 1 Chron. xxi. 5, 25 (2 Sam. xxiv. 9, 24); consequently little
importance can be attached to details which appear to be exaggerated
(1 Chron. v. 21, xii., xxii. 14; 2 Chron. xiii. 3, 17), and are found
to be quite in accordance with similar peculiarities elsewhere (Num.
xxxi. 32 seq.; Judg. xx. 2, 21, 25).

Historical value.

But when allowance is made for all the above tendencies of the late post-exilic age, there remains a certain amount of additional matter in _Chronicles_ which may have been derived from relatively old sources. These items are of purely political or personal nature and contain several details which taken by themselves have every appearance of genuineness. Where there can be no suspicion of such "tendency" as has been noticed above there is less ground for scepticism, and it must be remembered that the earlier books contain only a portion of the material to which the compilers had access. Hence it may well happen that the details which unfortunately cannot be checked were ultimately derived from sources as reputable as those in the books of Samuel, Kings, &c. As examples may be cited Rehoboam's buildings, &c. (2 Chron. xi. 5-12, 18 sqq.); Jeroboam's attack upon Abijah (2 Chron. xiii., cf. 1 Kings xv. 7); the invasion of Zerah in Asa's reign (2 Chron. xiv.; see ASA); Jehoshaphat's wars and judicial measures (2 Chron. xvii. xx.; see 1 Kings xxii. 45); Jehoram's family (2 Chron. xxi. 2-4); relations between Jehoiada and Joash (2 Chron. xxiv. 3, 15 sqq.); conflicts between Ephraim and Judah (2 Chron. xxv. 6-13); wars of Uzziah and Jotham (2 Chron. xxvi. seq.); events in the reign of Ahaz (2 Chron. xxviii. 8-15, 18 seq.); reforms of Hezekiah (2 Chron. xxix. sqq., cf. Jer. xxvi. 19); Manasseh's captivity, repentance and buildings (2 Chron. xxxiii. 10-20; see 2 Kings xxi. and MANASSEH); the death of Josiah (2 Chron. xxxv. 20-25). In addition to this reference may be made to such tantalizing statements as those in 1 Chron. ii. 23 (R.V.), iv. 39-41, v. 10, 18-22, vii. 21 seq., viii. 13, xii. 15, examples of the kind of tradition, national and private, upon which writers could draw. Although in their present form the additional _narratives_ are in the chronicler's style, it is not necessary to deny an older traditional element which may have been preserved in sources now lost to us.[9]

BIBLIOGRAPHY.--Robertson Smith's article in the 9th ed. of the _Ency.
Brit._ was modified by his later views in _Old Test. in the Jewish
Church_[2], pp. 140-148. Recent literature is summarized by S.R.
Driver in his revision of Smith's article in _Ency. Bib._ and in his
_Lit. of Old Test._, and by F. Brown in Hastings' _Dict. Bib._ (a very
comprehensive article). Many parts of the book offer a very hard task
to the expositor, especially the genealogies, where to other troubles
are added the extreme corruption and many variations of the proper
names in the versions; on these see the articles in the _Ency. Bib._
Valuable contributions to the exegesis of the book will be found in
Wellhausen's _Prolegomena_ (Eng. trans.), pp. 171-227; Benzinger in
Marti's _Hand-Kommentar_ (1901); Kittel in _Sacred Books of the Old
Test._ (1895), _History of the Hebrews_, ii. 224 sqq. (1896), and in
Nowack's _Hand-Kommentar_ (1902). W.H. Bennett in _Expositor's Bible_
(1894), W.E. Barnes in _Cambridge Bible_ (1899), and Harvey-Jellie in
the _Century Bible_ (1906), are helpful. Among more recent
investigations are those of Howorth, _Proc. Soc. of Bibl. Archael._
xxvii. 267-278 (Chronicles a late translation from the Aramaic).
(W.R.S.; S.A.C.)

FOOTNOTES:

[1] See the lists in Driver, _Lit. of Old Test._ pp. 502 sqq.; and the
exhaustive summary by Fr. Brown in Hastings' _Dict. Bible_, i. 289
sqq.

[2] R.V. "commentary," properly, an edifying religious work, a
didactic or homiletic exposition. A distinct tendency to Midrash is
found even here and there in the earlier books.

[3] The problem of the sources is one of considerable intricacy and
cannot be discussed here; the introduction to the commentaries of
Benzinger and Kittel (see _Bibliography_ below) should be consulted.
The questions depend partly upon the view taken of the origin and
structure of the book of Kings (q.v.) and partly upon the results of
historical criticism.

[4] "A careful comparison of Chronicles with Samuel and Kings is a
striking object lesson in ancient historical composition. It is an
almost indispensable introduction to the criticism of the Pentateuch
and the older historical works" (W.H. Bennett, _Chronicles_, p. 20
seq.).

[5] But xxxii. 1-8 may preserve a tradition of the account of the
city's wonderful deliverance mentioned in _Kings_ (see HEZEKIAH), and
the details of the invasion of Judah in the time of Joash differ
essentially from those in the earlier source. Even 2 Chron. viii. 2
cannot be regarded as a _deliberate_ alteration since the writer does
not appear to be quoting from 1 Kings ix. 10 sqq. (the two passages
should be carefully compared), and his view of Solomon's greatness is
already supported by allusions in the earlier but extremely composite
sources in _Kings_ (see SOLOMON).

[6] But that this was not the invention of the chronicler appears
possible from Jer. xxv. 3. Similarly, Hezekiah's reforms are dated in
his first year (2 Chron. xxix. 3), against all probability; see
HEZEKIAH (end).

[7] 2 Chron. xxiii. is an excellent specimen of the redaction to which
older narratives were submitted; cf. also 2 Chron. xxiv. 5 seq. (2
Kings xi. 4 seq.), xxxiv. 9-14 (2 Kings xxii.), xxxv. 1-19 (2 Kings
xxiii. 21-23).

[8] Passages in the books of Samuel and Kings which might appear to
point to the contrary require careful examination; they prove to be
glosses or interpolations, or are relatively late as a whole.

[9] The view that the chronicler _invented_ such narratives is
inconceivable, and in the present stage of historical criticism is
as unsound as an implicit reliance upon those sources in the earlier
books, which in their turn are often long posterior to the events
they record. Although Graf, in a critical and exhaustive study
(_Geschichtlichen Bücher des A.T._, Leipzig, 1866), concluded that
the Chronicles have almost no value as a documentary source of the
ancient history, he subsequently admitted in private correspondence
with Bertheau that this statement was too strong (preface to
Bertheau's _Commentary_, 2nd ed., 1873).

CHRONOGRAPH (from Gr. [Greek: chronos], time, and [Greek: graphein], to write). Instruments whereby periods of time are measured and recorded are commonly called chronographs, but it would be more correct to give the name to the records produced. Instruments such as "stop watches" (see WATCH), by means of which the time between events is shown on a dial, are also called chronographs; they were originally rightly called chronoscopes ([Greek: skopein], to see).

In the first experiments in ballistics by B. Robins, Count Rumford and Charles Hutton, the velocity of a projectile was found by means of the ballistic pendulum, in which the principle of momentum is applied in finding the velocity of a projectile (_Principles of Gunnery_, by Benjamin Robins, edited by Hutton, 1805, p. 84). It consisted of a pendulum of considerable weight, which was displaced from its position of rest by the impact of the bullet, the velocity of which was required. A modification of the ballistic pendulum was also employed by W.E. Metford (1824-1899) in his researches on different forms of rifling; the bob was made in the form of a long cylinder, weighing about 140 lb, suspended with its axis horizontal from four wires at each end, all moving points being provided with knife edges. The true length of suspension was deduced from observations of the time of a complete small oscillation. The head of the pendulum was furnished with a wooden block, which caught the fragments of bullets fired at it, and its displacement was recorded by a rod moved by the bob (_The Book of the Rifle_, by the Hon. T.F. Fremantle, p. 336). An improved ballistic pendulum in which the geometric method of suspension is introduced has been used by A. Mallock, to determine the resistance of the air to bullets having a velocity up to 4500 F/S. (_Proc. Roy. Soc._, Nov. 1904). A ballistic pendulum, carried by a geometric suspension from five points, has also been employed by C.V. Boys in a research on the elasticity of golf balls, the displacement of the bob being recorded on a sheet of smoked glass.[1] For further information on the dynamics of the subject see _Text Book of Gunnery_, 1897, p. 101.

In nearly all forms of chronographs in which the ballistic pendulum method is not used, the beginning and end of a period of time is recorded by means of some kind of electrically controlled mechanism; and in order that small fractions of a second may be measured, tuning-forks are employed, giving any convenient number of vibrations per second, a light style or scribing point, usually of aluminium, being attached to one of the legs of the tuning-fork. A trace of the vibration is made on a surface blackened with the deposit from the smoke of a lamp. Glazed paper is often employed when the velocity of the surface is slow, but when a high velocity of smoked surface is necessary, smoked glass offers far the least resistance to the movement of the scribing points. If the surface be cylindrical, thin sheet mica attached to it, and smoked, gives excellent results, and offers but little resistance to all the scribing points employed. The period of vibration of tuning-forks is determined by direct or indirect comparison with the mean solar second, taken from a standard clock, the rate of which is known from transit observations ("Recherches sur les vibrations d'un diapason étalon," R. Koenig, _Wied. Ann._, 1880). In the celebrated ballistic experiments of the Rev. F. Bashforth, the time markings were made electrically from a standard clock, and fractions of a second were estimated by interpolation. Regnault (_Mémoires de l'acad. des sciences_, t. xxxvii.) employed both a standard clock and a tuning-fork in his determination of the velocity of sound. The effect of temperature on tuning-forks has been determined by Lord Rayleigh and Professor H. McLeod (_Proc. Roy. Soc._, 1880, 26, p. 162), who found the coefficient to be 0.00011 per degree C. between 9° C. and 27° C. The beginning and end of a time period is marked on a moving surface in many ways. Usually an electromagnetic stylus is employed, in which a scribing point suddenly moves when the electric circuit is broken by a projectile. Another method is to arrange the terminals of the secondary circuit of an induction coil, so that when the primary circuit is opened a small spark punctures or marks a moving surface (Helmholtz, _Phil. Mag._, 1853, p. 6). A photographic plate or film, moving in a dark chamber, is also used to receive markings produced by a beam of light interrupted by a small screen attached to an electromagnetic stylus, or by the legs of a tuning-fork, or by the mercury column of a capillary electrometer. In certain researches on the explosive wave of gases the light given by the burning gases made the time trace on a rapidly moving photographic film (H.B. Dixon, _Phil. Trans._, 1903, 200, p. 323). In physiological chronography the stylus is in many cases actuated directly by the piece of muscle to which it is attached; when the muscle is stimulated its contraction moves the stylus on the moving surface of the myograph (M. Foster, _Text Book of Physiology_, 1879, p. 39).

Grobert and Dabooz.

_Gun Chronographs._--Probably the earliest forms of chronographs, not
based on the ballistic pendulum method, are due to Colonel Grobert,
1804, and Colonel Dabooz, 1818, both officers of the French army. In
the instrument by Grobert two large disks, attached to the same axle
13 ft. apart, were rapidly rotated; the shot pierced each disk, the
angle between two holes giving the time of flight of the ball, when
the angular velocity of the disks was known. In the instrument by
Colonel Dabooz a cord passing over two light pulleys, one close to the
gun, the other at a given distance from it, was stretched by a weight
at the gun end and by a heavy screen at the other end. Behind this
screen there was a fixed screen. The shot cut the cord and liberated
the screen, which was perforated during its fall. The height of fall
was measured by superposing the hole in the moving screen upon that in
the fixed one. This gave the approximate time of flight of the shot
over a given distance, and hence its velocity.

Wheatstone.

In the early form of chronoscope invented by Sir C. Wheatstone in 1840
the period of time was measured by means of a species of clock, driven
by a weight; the dial pointer was started and stopped by the action of
an electromagnet which moved a pawl engaging with a toothed wheel
fixed on the axle to which the dial pointer was attached. The
instrument applied to the determination of the velocity of shot is
described thus by Wheatstone:--"A wooden ring embraced the mouth of
the gun, and a wire connected the opposite sides of the ring. At a
proper distance the target was erected, and so arranged that the least
motion given to it would establish a permanent contact between two
metal points. One of the extremities of the wire of the electromagnet
(before mentioned) was attached to one pole of a small battery; to the
other extremity of the electromagnet were attached two wires, one of
which communicated with the contact piece of the target, and the other
with one of the ends of the wire stretched across the mouth of the
gun; from the other extremity of the voltaic battery two wires were
taken, one of which came to the contact piece of the target, and the
other to the opposite extremity of the wire across the mouth of the
gun. Before the firing of the gun a continuous circuit existed,
including the gun wire; when the target was struck the second circuit
was completed; but during the passage of the projectile both circuits
were interrupted, and the duration of this interruption was indicated
by the chronoscope."

Henry.

Professor Joseph Henry (_Journal Franklin Inst._, 1886) employed a
cylinder driven by clockwork, making ten revolutions per second. The
surface was divided into 100 equal parts, each equal to 1/1000 second.
The time marks were made by two galvanometer needles, when successive
screens were broken by a shot. Henry also used an induction-coil spark
to make the cylinder, the primary of the coil being in circuit with a
battery and screen. This form of chronograph is in many respects
similar to the instrument of Konstantinoff, which was constructed by
L.F.C. Breguet and has been sometimes attributed to him (_Comptes
rendus_, 1845). This chronograph consisted of a cylinder 1 metre in
circumference and 0.36 metre long, driven by clockwork, the rotation
being regulated by a governor provided with wings. A small carriage
geared to the wheelwork traversed its length, carrying electromagnetic
signals. The electric chronograph signal usually consists of a small
armature (furnished with a style which marks a moving surface) moving
in front of an electromagnet, the armature being suddenly pulled off
the poles of the electromagnet by a spring when the circuit is broken
(_Journal of Physiology_, ix. 408). The signals in Breguet's
instrument were in a circuit, including the screens and batteries of a
gun range. The measurement of time depended on the regularity of
rotation of the cylinder, on which each mm. represented 1/1000 second.

Navez.

In the chronograph of A.J.A. Navez (1848) the time period is found by
means of a pendulum held at a large angle from the vertical by an
electromagnet, which is in circuit with a screen on the gun range.
When the shot cuts this screen the circuit is broken and the pendulum
liberated and set swinging. When the next screen on the range is
broken by the shot, the position of the pendulum is recorded and the
distance it has passed through measured on a divided arc. From this
the time of traversing the space between the screens is deduced. By
means of an instrument known as a disjunctor the instrumental
time-loss or latency of the chronograph is determined. [Sidenote:
Benton.] In Benton's chronograph (1859) two pendulums are liberated,
in the same manner as in the instrument of Navez, one on the cutting
of the first screen, the other on the cutting of the second. The
difference between the swings of the two pendulums gives the time
period sought for. The disjunctor is also used in connexion with this
instrument. In Vignotti's chronograph (1857) again a pendulum is
employed, furnished with a metal point, which moves close to paper
impregnated with ferro-cyanide of potassium. The gun-range screens are
included in the primary circuits of induction coils; when these
circuits are broken a spark from the pointer marks the paper. From
these marks the time of traverse of the shot between the screens is
determined.

Bashforth.

In the Bashforth chronograph a platform, arranged to descend slowly
alongside of a vertical rotating cylinder, carries two markers,
controlled by electromagnets, which describe a double spiral on the
prepared surface of the cylinder. One electromagnet is in circuit with
a clock, and the marker actuated by it marks seconds on the cylinder;
the circuit of the other is completed through a series of contact
pieces attached to the screens through which the shot passes in
succession. On the gun range, when the shot reaches the first screen,
it breaks a weighted cotton thread, which keeps a flexible wire in
contact with a conductor. When the thread is broken by a shot, the
wire leaves the conductor and almost immediately establishes the
circuit through the next screen, by engaging with a second contact,
the time of the rupture being recorded on the cylinder by the second
marker. The velocity with which the cylinder rotates is such that the
distance between successive clock marks indicating seconds is about 18
in.; hence the marks corresponding with the severance of a thread can
be allotted their value in fractions of seconds with great accuracy.
The times when the shot passes successive screens being thus recorded
on the spiral described by the second marker, and the distance between
each screen being known, the velocity of the shot can be calculated.

Noble.

The chronoscope invented by Sir Andrew Noble is so well adapted to the
measurement of very small intervals of time that it is usually
employed to ascertain the velocity acquired by a shot at different
parts of the bore in moving from a state of rest inside the gun. A
series of "cutting plugs" is screwed into the sides of the gun at
measured intervals, and in each is inserted a loop of wire which forms
part of the primary circuit of an induction coil. On the passage of a
shot this wire is severed by means of a small knife which projects
into the bore and is actuated by the shot as it passes; the circuit
being thus broken, a spark passes between the terminals of the
secondary of the coil. There is a separate coil and circuit for each
plug. The recording arrangement consists of a series of disks, one for
each plug, mounted on one axle and rotating at a high angular
velocity. The edges of these disks are covered with a coating of
lamp-black, and the secondaries of the coils are caused to discharge
against them, so that a minute spot burnt in the lamp-black of each
disk indicates the moment of the cutting of the wire in the
corresponding plug. Hence measurement of the distance between two
successive spots gives the time occupied by the shot in moving over
the portion of the bore between two successive plugs. By the aid of a
vernier, readings are made to thousandths of an inch, and the
peripheral velocity of the disks being 1100 in. a second, the machine
indicates portions of time rather less than one-millionth of a second;
it is, in fact, practically correct to hundred-thousandths of a second
(_Phil. Trans._, 1875, pt. i.).

Le Boulengé.

In the Le Boulengé chronograph ("Chronograph le Boulengé," par M.
Bréger, Commission de Gâvre, Sept. 1880) two screens are used. The
wire of the first forms part of the circuit of an electromagnet which,
so long as it is energized, supports a vertical rod called the
"chronometer." Hence when the circuit is broken by the passage of a
shot through the screen this rod drops. The wire of the second screen
conveys a current through another electromagnet which supports a much
shorter rod. This "registrar," as it is called, when released by the
shot severing the wire of the second screen, falls on a disk which
sets free a spring, and causes a horizontal knife to fly forward and
nick a zinc tube with which the chronometer rod is sheathed. Hence the
long rod will be falling for a certain time, while the shot is
travelling between the two screens, before the short rod is released;
and the longer the shot takes to travel this distance, the farther the
long rod falls, and the higher up on it will be the nick made by the
knife. A simple calculation connects the distance through which the
rod falls with the time occupied by the shot in travelling over the
distance between the screens, and thus its velocity ascertained. The
nick made by the knife, if released while the chronometer rod is still
suspended, is the zero point. If both rods are released
simultaneously, as is done by breaking both circuits at once by means
of a "disjunctor," a certain time is consumed by the short rod in
reaching the disk, setting free the spring and cutting a nick in the
zinc; and during this time the long rod is falling into a recess in
the stand deep enough to receive its full length. The instrument is so
adjusted that the nick thus made is 4.435 in. above the zero point,
corresponding to 0.15 sec. This is the disjunctor reading, and
requires to be frequently corrected during experiments. The instrument
was modified and improved by Colonel H.C. Holden, F.R.S. For further
information respecting formulae relating to it see _Text Book of
Gunnery_ (1857).

Watkin.

The electric chronograph of the late H.S.S. Watkin consists of two
long cylinders rotating on vertical axes, and between them a
cylindrical weight, having a pointed head, is free to fall. The weight
is furnished with an insulated wire which passes through it at right
angles to its longest axis. When the weight falls the ends of the
insulated wire move very close to the surfaces of the cylinders which
form part of a secondary circuit of an induction coil, the primary
circuit of which is opened when a screen is ruptured by a shot. A
minute mark is made by the induced spark on the smoked paper with
which the cylinders are covered. The time period between events is
deduced from the space fallen through by the weight, and by means of a
scale, graduated for a given distance between the screens, the
velocity of a shot is at once found. It may be noted that the method
of release is such that the falling weight is not subjected, after it
has begun to fall, to a diminishing magnetic field, which would be the
case if it were directly supported by an electromagnet. An iron rod
when falling from an electromagnet, during a minute portion of its
fall, is subject to a diminishing force acting in the opposite sense
to that of gravity, whereby its time of fall is slightly changed.

Colonel Sebert (_Extraits du mémorial de l'artillerie de la marine_)
devised a chronograph to indicate graphically the motion of recoil of
a cannon when fired. A pillar fixed to the ground at the side of the
gun-carriage supported a tuning-fork, the vibration of which was
maintained electrically. The fork was provided with a tracing point
attached to one of the prongs, and so adjusted that it drew its path
on a polished sheet of smoke-blackened metal attached to the
gun-carriage, which traversed past the tracing point when the gun ran
back. The fork used made 500 complete vibrations per second. A central
line was drawn through the curved path of the tracing point, and every
entire vibration cut the straight line twice, the interval between
each intersection equalling 1/1000 second. The diagram so produced
gave ihe total time of the accelerated motion of recoil of the gun,
the maximum velocity of recoil, and the rate of acceleration of recoil
from the beginning to the end of the motion. By means of an instrument
furnished with a microscope and micrometers, the length and amplitude,
and the angle at which the curved line cut the central line, were
measured. At each intersection (according to the inventor) the
velocity could be deduced. The motion at any intersection being
compounded of the greatest velocity of the fork, while passing through
the midpoint of the vibration and the velocity of recoil, the tangent
made by the curve with the straight line represents the ratio of the
velocity of the fork to the velocity of recoil. If a be the amplitude
of vibration, considered constant, v the velocity of the fork at the
midpoint of its path, r the velocity of recoil, [alpha] the angle made
by the tangent to the curve with the straight line at the point of
intersection, and t the line of a complete vibration; then, v =
2[pi]a/t; r = v/tan [alpha].

Jervis-Smith.

F. Jervis-Smith's tram chronograph (_Patents_, 1894, 1897, 1903) was
devised for measuring periods of time varying from about one-fourth to
one twenty-thousandth part of a second (_Proc. Roy. Soc._, 1889, 45,
p. 452; _The Tram Chronograph_, by F. Jervis-Smith, F.R.S.). It
consists of a metal girder having a T-shaped end. This carries two
parallel steel rails, the edges of which lie in the same vertical
plane. The girder, which is slightly inclined to the horizontal plane,
is geometrically supported, being carried at its end, and at the
extremities of the T-piece, on a V-groove, trihedral hole and plane. A
carriage or tram furnished with three grooved wheels runs on the
rails, and a slightly smoked glass plate is attached to its vertical
side. The tram in the original instrument was propelled by a falling
weight, but in an improved form one or more spiral springs are
employed. All time traces are made immediately after the propelling
force has ceased to act. The tram is brought to rest by a gradually
applied brake, consisting of two crossed leather bands stretched by
two springs; a projection from the tram runs between the bands, and
brings it to rest with but little lateral pressure. When, for certain
physiological experiments, a low velocity of traverse is required, a
heavy fly-wheel is mounted on the tram and geared to its wheels. A
pillar also mounted geometrically, placed vertically in front of the
carriage, carries the electromagnet style or signals and tuning-fork
which can be brought into contact with the glass by means of a lever.
Also styli are used which depend for their action on the displacement
of one or more wires under tension or torsion carrying a current in a
magnetic field, the condition being such that no magnetic lag due to
iron armatures and cores exists. Two motions of a slide on the pillar,
viz. of rotation and translation, allow a number of observations to be
made. The traces are counted out on a sloping glass desk, and the time
of flight of a projectile between two or more screens is found. When
very close readings are required, they are made by means of a
traversing geometric micrometer microscope. When the distance between
the screens is known, and also the time of flight, the midpoint
velocity is found by applying Bashforth's formula. When the velocity
of shot from a shot-gun has to be found, a thin wire stretched across
the muzzle takes the place of the first screen, and a thin sheet of
metal or cardboard carrying an electric contact, or a Branly coherer,
the conductivity of which is restored by means of an induced current,
takes the place of the second screen. The electric firing circuit is
provided with a safety key attached by a cord to the man who loads the
gun and prepares the electric fuse. The firing circuit is closed by
inserting the key in a switch at the rear of the gun, thus preventing
him from getting into the line of fire when the gun is fired by the
chronograph. The tram, when the instrument is adjusted, has a
practically constant velocity of traverse.

Crehore-Squier.

The polarizing photo-chronograph, designed and used by A.C. Crehore
and G.O. Squier at the United States Artillery School (_Trans. Amer.
Inst. Elect. Eng._ vol. 14, and _Journal United States Artillery_,
1895, 6, p. 271), depends for its indications upon the rotation of a
beam of light by a magnetic field, produced by a solenoidal current
which is opened and closed by the passage of the projectile. The
general arrangement is as follows:--A beam of light from an electric
lamp traverses a lens, then a Nicol prism, next a glass cylinder
furnished with plane glass ends and coiled with insulated wire, then
an analyser and two lenses, finally impinging on a photographic plate
to which rotation is given by an electric motor, the plane of rotation
being perpendicular to the direction of the beam of light. The same
plate also records the shadow of a pierced projection attached to a
tuning-fork, light from the electric lamp being diverted by a mirror
for this purpose. The solenoid used to produce a magnetic field across
the glass cylinder, which is filled with carbon bisulphide, is in
circuit with a dynamo, resistances, and the screens on the gun range.
It is a well-known phenomenon in physics that when, with the
above-mentioned combination of polarizing Nicol prism and analyser,
the light is shut off by rotating the analyser, it is instantly
restored when the carbon bisulphide is placed in a magnetic field.
This phenomenon is utilized in this instrument. The projectile, by
cutting the wire screens, causes the magnetic field to cease and light
to pass. By means of an automatic switch the projectile, after cutting
a screen, restores the electric circuit, so that successive records
are registered. After a record has been made it is read by means of a
micrometer microscope, the angle moved through by the photographic
disk is found, and hence the time period between two events. In the
photo-chronograph described in _Untersuchungen über die Vibration des
Gewehrlaufs_, by C. Cranz and K.R. Koch (Munich, 1899), also note on
the same, _Nature_, 61, p. 58, a sensitive plate moving in a straight
line receives the record of the movement of the barrels of firearms
when discharged. It was mainly used to determine the "angle or error
of departure" in ballistics.

Watkin.

In a second chronograph by Watkin ("Chronographs and their Application
to Gun Ballistics," _Proc. Roy. Inst._, 1896), a metal drum, divided
on its edge so that when a vernier is used a minute of angle may be
read, is rotated rapidly by a motor at a practically uniform speed.
The points of a row of steel-pointed pins, screwed into a frame of
ebonite, can be brought within 1/200 in. of the surface of the drum.
Each pin is a part of the secondary circuit of an induction coil, the
space between the pins and the drum forming spark-gaps. The drum is
rubbed over with a weak solution of paraffin wax in benzol, which
causes the markings produced by the sparks to be well defined. The
records are read by means of a fine hair stretched along the drum and
just clear of it, the dots being located under the hair by means of a
lens. The velocity of rotation is found by obtaining spark marks, due
to the primary circuits of two induction coils being successively
broken by a weight falling and breaking the two electric circuits of
the coils in succession at a known distance apart. This chronograph
has been used for finding the velocity of projectiles after leaving
the gun, and also for finding the rate at which a shot traverses the
bore. For the latter purpose the shot successively cuts insulated
wires fixed in plugs screwed into the gun at known intervals; each
wire forms a part of the primary of an induction coil, and as each is
cut a dot is made on the rotating drum by the induced spark.

Deprez.

In the chronograph of Marcel Deprez, a cylinder for receiving records
is driven at a high velocity, 4 to 5 metres per second surface
velocity. The velocity is determined by means of an
electrically-driven tuning-fork, the traces being read by means of a
vernier gauge. A mercury speed indicator of the Ramsbottom type
enables the rotation to be continuously controlled (A. Favarger,
_L'Électricité et ses applications à la chronométrie_).

Dent.