Chapter C: N. PICKWORTH, Withington, Manchester

┌─────────────────────────────────────────────────────────────────────┐ │ W. P. THOMPSON, G. C. DYMOND, │ │ F.C.S., M.I.Mech.E., F.I.C.P.A. M.I.Mech.E., F.I.C.P.A. │ │ │ │ W. P. Thompson & Co., │ │ 12 CHURCH STREET, LIVERPOOL, │ │ CHARTERED PATENT AGENTS. │ │ │ │ H. E. POTTS, J. V. ARMSTRONG, │ │ M.Sc., Hon. Chem., F.I.C.P.A. M.Text.I., F.I.C.P.A. │ │ │ │ W. H. BEESTON, R.P.A. │ └─────────────────────────────────────────────────────────────────────┘

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BRITISH
SLIDE RULES

for all
ARTS and
INDUSTRIES

including

]

_LOG-O-LOG
DR. YOKOTA’S
SURVEYORS’
WIRELESS
GUNNERY
ELECTRICAL RULES, Etc._

SEND FOR LIST 55

MADE BY—

JOHN DAVIS & SON (Derby), Ltd.
ALL SAINTS’ WORKS, DERBY

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K & E Slide Rules

are constantly growing in popularity, and they can now be obtained from the leading houses in our line throughout the United Kingdom.

]

We manufacture a complete line of ENGINE-DIVIDED SLIDE RULES, and call special attention to our Patent Adjustment, ensuring smooth working of the Slide; also to our new “Frameless” Indicator, which hides no figures on the Rule.

]

THACHER’S CALCULATING INSTRUMENT, for solving problems in multiplication, division, or combinations of the two; has upwards of 33,000 divisions. Results can be obtained to the fourth and usually to the fifth place of figures with a surprising degree of accuracy.

We also make

ALL METAL, CIRCULAR, STADIA, CHEMISTS’, ELECTRICAL, and OTHER SPECIAL
SLIDE RULES
_DESCRIPTIVE CIRCULARS ON REQUEST_

KEUFFEL & ESSER CO.
127 Fulton St., NEW YORK General Office and Factories, HOBOKEN,
N.J.
CHICAGO − ST. LOUIS − SAN FRANCISCO − MONTREAL

_DRAWING MATERIALS_
_MATHEMATICAL and SURVEYING INSTRUMENTS_
_MEASURING TAPES_

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NORTON
&
GREGORY
LTD.

Head Office

CASTLE LANE, WESTMINSTER, LONDON, S.W. 1

Branches

71 QUEEN STREET, GLASGOW.
PHOENIX HOUSE, QUEEN STREET and SANDHILL, NEWCASTLE-ON-TYNE.

SLIDE RULES in Stock, from 17/6 to 27/6

Special Quotations to the Trade for Quantities

For particulars of Surveying, Measuring and Mathematical Instruments,
Appliances and Material of all kinds for the Drawing Office, write
to the Head Office.

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NORTON & GREGORY, LTD.,
London.

“DIAMOND”
DRAWING INSTRUMENTS
Manufactured at our London Works.

CENTRE SCREW SPRING BOW HALF SET.

]

4 inch Spring Bow Half Set centre screw adjustment, with interchangeable needle, pen, and pencil points Price 17/6

The Centre Screw Spring Bow Half Set of Compasses, as illustrated, possesses the advantage of COMBINING IN ONE INSTRUMENT THE SET OF THREE SEPARATE SPRING BOWS hitherto in use, while the centre screw makes for ease and accuracy of manipulation, at the same time providing a radius of over 2 inches, or double that of the old pattern.

This instrument is less expensive than the set of 3 bows, while considerably stronger in construction.

The fixed needle point is shouldered.

This illustration is given as an indication of the various Drawing Instruments manufactured by us.

Illustrated Booklet giving full particulars and prices of other Instruments and Cases of Instruments sent on application.

Specially arranged Sets of Instruments made for Colleges, Schools,
Technical Institutes

Estimates submitted on Application.

_Write to our Head Office_:
CASTLE LANE, WESTMINSTER, LONDON, S.W. 1.

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DRAWING AND SURVEYING INSTRUMENTS

A. G. THORNTON Ltd.
SLIDE RULES FOR Paragon Works ACCURATE SECTIONAL
ENGINEERS 2 King St. West PAPERS AND CLOTHS
MANCHESTER

D 1916 Illustrated Catalogue, just published, in two editions; Drawing
Office (448 pages); Draughtsman’s (160 pages): the most complete
Catalogues in the trade.

_CONTRACTORS TO H.M. WAR OFFICE AND ADMIRALTY_
_Manufacturers also of Drawing Materials and Drawing Office Stationary._

(ALSO AT MINERVA WORKS AND ALBERT MILLS, MANCHESTER.)

MATHEMATICAL INSTRUMENTS
SURVEYING INSTRUMENTS
SLIDE RULES
For Students and Engineers

MANNHEIM, POLYPHASE, DUPLEX, ELECTRICAL, LOG-LOG, AND CALCULEX

J. H. STEWARD LTD.
Scientific Instrument Makers

406 STRAND, and 457 WEST STRAND
LONDON, W.C. 2

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_A True Friend and Trusty Guide_

THE
‘HALDEN CALCULEX’

]

ACTUAL SIZE| | | BRITISH MADE

The handiest and most perfect form of Slide Rule.
Does all that can be done with a straight rule.
Complete in Case, with book of instructions,
27/6 post free.

J. HALDEN & CO., LTD., 8 ALBERT SQUARE MANCHESTER

_Depots_—London, Newcastle-on-Tyne, Birmingham, Glasgow, and Leeds

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]

ENGINEERING,
SURVEYING
AND
MATHEMATICAL
INSTRUMENTS,
ETC.

SLIDE RULES.

JOSEPH CASARTELLI & SON,
43 MARKET STREET, MANCHESTER.
Tel. No. 2958 City.| | | Established 1790.

ROPE DRIVING

Is the most EFFICIENT and most ECONOMICAL METHOD of Power
Transmission.

The LAMBETH Cotton Driving Rope

Is the most EFFICIENT and most ECONOMICAL ROPE for Power Transmission.

SPECIAL FEATURES:

LESS STRETCH THAN ANY OTHER ROPE. MORE PLIABLE THAN ANY OTHER ROPE.
GREATER DRIVING POWER THAN ANY OTHER ROPE.

THOMAS HART LTD., Lambeth Works, BLACKBURN.

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TRANSCRIBER’S NOTES

Page Changed from Changed to

24 the right, so the number of the right, so the number of
digits in the answer = 3 − 2 × 1 digits in the answer = 3 − 2 + 1
= 2 = 2

116 grammes, we have the equation, grammes, we have the equation,
_x_ × (Cl.)/(Ag.Cl.) × _x_ = (Cl.)/(Ag.Cl.) ×
(_a_)/(_s_). Hence, the mark (_a_)/(_s_). Hence, the mark

● Typos fixed; non-standard spelling and dialect retained. ● Used numbers for footnotes, placing them all at the end of the last chapter. ● Enclosed italics font in _underscores_. ● Enclosed bold font in =equals=. ● The caret (^) serves as a superscript indicator, applicable to individual characters (like 2^d) and even entire phrases (like 1^{st}). ● Subscripts are shown using an underscore (_) with curly braces { }, as in H_{2}O.