Chapter XVIII: Mercury

BY F. L. RANSOME

USES OF MERCURY

Under normal conditions the chief uses of quicksilver (mercury) or its salts, stated in order of decreasing importance, are as follows: In the manufacture of drugs and chemicals, including calomel and corrosive sublimate; in the manufacture of certain chemicals, such as glacial acetic acid, phthalic acid and phthalic anhydride, into which mercury itself does not enter; as mercury fulminate ((C:N.O₂)Hg, ¹⁄₂H₂O), made by treating mercury with alcohol and nitric acid, which is used as a detonator for high explosives, and, though less than formerly, in small-arms ammunition.

The discovery of mercury fulminate by Howard in 1799 led to the invention of the percussion cap in place of the old flint-lock, and fulminate still remains the best-known and most-used detonator for gunpowder and high explosives. It is often combined with other substances, particularly an abrasive such as powdered glass, to increase its sensitiveness, and with compounds or mixtures that themselves have the property of detonating, such as sulphide of antimony and chlorate of potassium. Recently a large part of the mercury fulminate in detonators for modern high explosives has been replaced by picric acid, trinitrotoluene, or tetranitromethylamine, whereby a much stronger initial effect is obtained, and one part of mercury fulminate is made to detonate a charge that would have required six times as much fulminate used alone. Other substances have been found, which seem likely to replace mercury fulminate entirely for certain uses. One of these is lead azide, a salt of hydronitric acid. Large dry crystals of this salt are so sensitive as to explode when brushed with a feather, but smaller crystals are less sensitive.

As mercuric sulphide, mercury forms the brilliant red pigment _vermilion_. The metal is employed extensively in electrical apparatus, including rectifiers for changing alternating into direct current, mercury vapor lamps, and storage batteries. In the manufacture of felt hats from rabbits’ fur, mercuric nitrate is used to roughen the hairs so that they will adhere together, a process technically known as “carroting.” Metallic quicksilver is employed in the amalgamation of gold and silver ores, although of late years the wide application of the cyanide process has decreased this use. The metal is also utilized in the manufacture of instruments, thermostats, gas governors, and other appliances. Mercury enters into the composition of some anti-fouling marine paints for ship bottoms, a modern and at present rapidly increasing use. The mercury for this purpose is generally employed as red mercuric oxide, its efficiency depending upon the gradual conversion of the oxide to the poisonous bichloride by the sodium chloride of salt water. Mercury is also used in certain compounds for preventing boiler scale, in cosmetics, and in dental amalgam. Silver nitrate has to a large extent replaced mercury in silvering mirrors. A small quantity of quicksilver, not more than two or three flasks annually, is used in floating certain types of revolving lights in lighthouses. Quicksilver is also used as the cathode in certain electrolytic processes for manufacturing chlorine and caustic soda from common salt. Mercuric oxide parts with oxygen readily and is a useful oxidizing agent in certain chemical processes. An important modern utilization of this property is in the manufacture of glacial acetic acid by the oxidation of acetylene.

Experiments to determine the possible advantages of using mercury vapor with steam in turbine power generators are reported to have been encouraging and a 4,000-kilowatt unit has been built by the General Electric Co. to test further this application. Except for incidental losses, the mercury so used is recoverable, but if in practice the increase of power is as much as the experimental work has indicated a large consumption of the metal is likely to result.

The production of quicksilver in this country in 1917 was 35,954 flasks (of 75 pounds) and in 1918 it was 32,883 flasks.

GEOLOGICAL DISTRIBUTION

The ores of quicksilver, like those of most metals, show on the whole a close association with igneous rocks and with zones of fissuring. More commonly than with other metals, with the possible exception of antimony, they are associated with volcanism as opposed to plutonic igneous activity and were deposited comparatively near the surface. It follows that quicksilver deposits as a rule are found in regions of Tertiary and Quaternary volcanic activity which have not been subjected to long and deep erosion, that they are more likely to be in the younger geologic formations than in the older rocks, and that as a class, compared for example with the hypogene ores of gold or copper, do not extend to great depth. It must be noted, however, that there are some conspicuous exceptions to these generalizations. Although the California deposits are in a region of late volcanic activity and many of them are closely associated with active hot springs, the ore bodies that are now most productive, those at New Idria (Idria post office) and the great deposits, at New Almaden, that formerly yielded so richly, have no obvious connection with volcanism. The greatest quicksilver mine in the world, that at Almaden, Spain, has no known connection with volcanism or massive igneous rocks, has been worked to a depth of 1,150 feet, and the ore bodies have been found to grow larger and richer downward. The deepest quicksilver mine in the world is the New Almaden in California, worked to a depth of 2,200 feet. The part of the mine below the 600-foot level was abandoned at a time when the price of quicksilver was low, but it is doubtful whether, under any conditions that can now be foreseen, it will be profitable to reopen and work the deep levels of this mine.

Although most of the known quicksilver deposits are in regions of geologically late volcanic eruptions it is probable that ores of quicksilver were deposited during or closely following epochs of similar igneous activity in the older geologic periods, but that many of them have been removed by erosion. Some of the deposits in the older rocks, which do not appear to be related to Tertiary or later volcanic eruptions, may have had such earlier origin.

The quicksilver deposits of the Adriatic region in Europe, including those at Idria, in Austria; Avala, in Serbia; and Monte Amiata, in Italy, have been shown by De Launay to belong to a single metallogenetic province characterized by Tertiary eruptions. Similarly, the somewhat scattered occurrences of quicksilver in Alaska, Washington, Idaho, Montana, Oregon, Nevada, Utah, California, Arizona, Mexico, Peru, and Chile coincide in part with the belt of Tertiary and Quaternary volcanic activity along the western sides of the continents of North and South America. The deposits at Almaden, Spain, in the Donetz basin, Russia, in Asiatic Turkey, and in China appear to be isolated occurrences that can not at present be assigned to recognizable provinces of eruptive activity and metallization.

Quicksilver deposits are not confined to rocks of any particular kind or of any particular geologic age.

At Oviedo the ore averages 0.33 per cent. and yields arsenic compounds as by-products. At Idria the ore yields 0.65 per cent. The ore of the Abbadia-San Salvatore, the principal mine in the Monte Amiata district, in Italy, yielded about 0.9 per cent. in 1915. In California few mines have over 2 per cent. ore, and the average yield of the ore worked is about 0.5 per cent. The lowest yield that was profitably obtained in that state in 1917 was 0.185 per cent. The ores worked in Texas are generally of higher grade than those mined in California. In the principal mine of the Terlingua district, Texas, the won tenor of the ore in 1916 was 2.5 per cent. and in 1917, 3.9 per cent.

GEOGRAPHICAL DISTRIBUTION

=Europe.=--The largest and richest deposit of quicksilver ore known is at Almaden, in central Spain. There are three nearly parallel ore bodies standing vertically side by side, each consisting of a portion of a bed of quartzite of Silurian age, impregnated with cinnabar. The ore bodies have been mined to a depth of 350 meters. The production in 1917 was probably about 25,000 flasks. The mine is said to have ore opened up that insures a future production of at least 40,000 metric tons of quicksilver. Other productive deposits in Spain are those near Oviedo, where the ore, which contains cinnabar, pyrite, orpiment, and realgar, is said to average about one-third of 1 per cent. of quicksilver, with arsenic compounds as by-products. According to a report from Vice Consul General H. A. McBride, written in Barcelona in 1911, the principal companies operating in the Oviedo districts were the Oviedo Mercury Mines Co., Ltd., of London, the Sociedad Fabrica de Mieres, of Oviedo, and the Sociedad Union Asturiana, of Mieres. The production from the district in 1915 was 608 flasks (20.7 metric tons). A third group of deposits lies on the south slope of the Sierra Nevada in the provinces of Granada and Almeria, southern Spain. The production from Granada in 1915 was 41 flasks (1.4 metric tons).

A small quantity of quicksilver was produced in _Portugal_ in the nineteenth century from a mine not far from Lisbon. Cinnabar occurs at a number of localities in _France_ and also in Corsica, but the deposits are not of economic character.

In South _Germany_, north of Zweibrucken, are quicksilver deposits that had considerable importance near the end of the thirteenth century, but at the beginning of the World War the mines had been closed for many years. Zinc ores mined near Bensberg, east of Cologne, yield annually about 90 flasks of quicksilver, won as a by-product in zinc smelting. In the former _Austrian Empire_ the principal deposit is at Idria, about 28 miles from Trieste. The ore body occurs chiefly as an impregnation of Triassic dolomite and shale. The output in Austria in 1916, probably all from Idria, is believed to have been about 25,000 flasks. Reserves capable of yielding 20,000 metric tons, or 587,733 flasks, are known. At latest reports these mines were in the possession of Italy. At Zips, in northern _Hungary_, quicksilver is obtained as a by-product from iron ore (siderite) that carries mercurial tetrahedrite and some cinnabar. The production in 1913 was 2,615 flasks.

To the west of Idria, quicksilver deposits belonging to the same general belt of metallization extend into northern _Italy_. The principal deposit of this belt in Venetia is the Vallalta. The mine produced 9,550 flasks (325 metric tons) between 1856 and 1870, but has long been idle. The most productive deposits of quicksilver in Italy are those of the Monte Amiata district, in Tuscany, about half way between Rome and Florence. Monte Amiata is apparently a post-Pliocene volcano, and traces of recent volcanic activity survive. The most productive mine is the Abbadia-San Salvatore, which yields about 65 per cent. of the output from the district, which in 1917 amounted to about 29,300 flasks.

At Mount Avala, near Belgrade in _Serbia_, deposits of quicksilver ore have been known since 1883, which resemble many of those in California. The Avala deposits were worked between 1889 and 1895, but seemingly have not been productive in late years.

The only quicksilver deposits of note in European _Russia_ are those in the Donetz coal basin, southern Russia. The essential mineral is cinnabar, accompanied by stibnite and pyrite. The deposits were discovered in 1879, the maximum output, 18,102 flasks (616 metric tons), was reached in 1897, and work was abandoned in 1911, but has been resumed since in a small way.

=Asia.=--The Konia mine, in south-central _Asia Minor_, is in silicified limestone. The quicksilver occurs as cinnabar and most of the ore carries from 1 to 2.5 per cent. of the metal. The known reserves were estimated in 1908 at 13,000 metric tons of 1 per cent. ore. The production in 1911 was only 90 flasks of 75 pounds. The Kara-Burnu mine, said to be the only important quicksilver mine in Turkey, is situated southeast of Smyrna. In 1906 and 1907 the mine was producing about 3,000 flasks annually, but of late years the output has declined and in 1912 amounted to only 811 flasks (31 metric tons).

The Ildekansk quicksilver mine, in southeastern _Siberia_, east of Lake Baikal, has gained notoriety from the fact that political exiles were condemned to mine the ore. The deposit appears to be of slight economic importance.

That quicksilver deposits occur in the Province of Kweichow, south-central _China_, has long been known, but the locality is remote from ordinary routes of travel and comparatively little is on record concerning their character. The ore bodies of the Wan San Chang mines are the most extensively worked. For several years prior to 1905 the output averaged about 4,000 pounds of quicksilver a month. This would be equivalent to about 640 flasks annually. More recent figures of production are not available.

=North America.=--The quicksilver deposits of North America are confined to the Cordilleran region from Alaska to Central America. The most productive deposits are in California and western Texas. In _Alaska_ minerals containing quicksilver have been found in a number of the placer-mining districts, but deposits in place have been discovered in the central Kuskokwim region only. The ore occurs as cinnabar accompanied by stibnite, quartz, and a ferruginous dolomite. Development has been hindered by transportation difficulties, and only a few hundred pounds of quicksilver have been produced for local consumption. In _Washington_ quicksilver ores have been prospected in various places, but the production is as yet inconsiderable. In _Oregon_ cinnabar is widely distributed, but only one deposit (at Blackbutte, in Lane County) is at present productive. In the Black Butte mine the ore averages about 0.25 per cent. of quicksilver, and the quantity available above the 500-foot level is estimated by the company at about 150,000 tons. The production of Oregon in 1917 was 388 flasks, all but 3 flasks being from the Black Butte mine.

In _California_ the principal deposits occur in the Coast Ranges within a belt that is about 400 miles long and has a maximum width of about 75 miles. The known deposits within this area are numerous. About twenty-five of these are at present productive, while probably three times that number which were once productive are now idle. With a few exceptions, the deposits of this main quicksilver belt are in rocks of probable Jurassic age, or in serpentine which is the alteration product of peridotites. The most notable exceptions are the deposits of the Oceanic mine, San Luis Obispo County, and of the Sulphur Bank mine, in Lake County. Many of the most productive mines of the past have yielded no quicksilver from underground work for years.

The most productive mine in California at present is the New Idria, in San Benito County, which in 1917 yielded 11,000 flasks out of a total for the state of 23,733 flasks and for the United States of 35,954 flasks. The New Idria ore comes from two mines, the New Idria proper and the San Carlos. The New Idria has been extensively opened to a depth of about 1,000 feet. In the San Carlos practically all of the known ore lies within 200 feet of the surface. The two mines contributed nearly equally to the total production in 1917, and the average winnable tenor of the ore in that year was 0.32 per cent. It has been estimated that in the two mines there is available 2,400,000 tons of ore averaging 0.253 per cent. of quicksilver.

The New Almaden mine is in Santa Clara County. At present, all the levels below the 800-foot are under water and of late years very little ore has been taken from the old mine. Most of the recent production of the New Almaden Co., Inc., which for 1917 amounted to 2,683 flasks, has come from the El Senador mine, northeast of the old mine, and from quicksilver recovered from ground under old furnaces and condensers. In the New Almaden, the El Senador, and in the neighboring New Guadalupe, which produced 3,100 flasks in 1917, the ore occurs as irregular bodies in serpentine. Close to the mine now being worked by the New Guadalupe Mining Co., and owned by the same company, is the original Guadalupe mine, once highly productive but now long idle.

The Oceanic mine, in San Luis Obispo County, ranked fourth in productiveness in California in 1917, with an output of 1,246 flasks. The ore occurs as an impregnation of sandstone. The average winnable tenor of the ore in 1917 was 0.185 per cent. Other mines in California which yielded from 500 to 1,000 flasks in 1917 are the Great Eastern, the Cloverdale, and the Culver-Baer, all in Sonoma County. Those whose output was between 400 and 500 flasks are the St. Johns, and the Helen, in Lake County.

_Nevada_ contains many widely scattered deposits of quicksilver ore, no one of which has yet been worked on an extensive scale, although a few have been fairly productive for short periods. The ores occur in rhyolite of Tertiary age and in limestone or associated sedimentary beds of various ages from Paleozoic to Mesozoic. The total yield from Nevada in 1917 was 997 flasks, nearly half of which came from the Farnham and Drew mine, east of Mina, which closed for lack of ore near the end of the year. The next mine in point of yield, the Goldbanks, in Humboldt county, is also at present non-productive.

In _Texas_ the principal quicksilver deposits are in the Terlingua district, in Brewster County. The ore occurs along fissure zones in Cretaceous limestones and shales, generally in proximity to intrusive rock. The principal mines are the Chisos, Mariposa, Big Bend, and Dallas.

In _Mexico_ quicksilver deposits in the states of San Luis Potosi, Guerrero, and Durango are said to be yielding considerable quicksilver, even in the present disturbed condition of the country. A quicksilver dealer, testifying at the Tariff Commission hearing in San Francisco, on June 26, 1918, said that 400 flasks a month was being exported into the United States, but a considerable part of this was probably reclaimed quicksilver that has been used in the amalgamation of silver ores.

=South America.=--Quicksilver deposits are known in Colombia, Ecuador, Bolivia, Chile, Brazil, Argentina, and Peru, but only those in Peru seem to be of present economic importance, and the production of that country in 1916 was only 62 flasks (2.1 metric tons). The most famous deposits in Peru are those at Huancavelica, particularly those of the Santa Barbara mine, on the east flank of the western chain of the Andes. These have been worked since 1566 and are said to have yielded 46,500 metric tons (1,366,480 flasks of 75 pounds) before 1790. The production in the 19th century has been estimated at 3,500 metric tons (102,865 flasks). The ore bodies are numerous, irregular, and occur in stratified rocks that are cut by igneous rocks. In 1916 the greater part of the quicksilver-bearing ground in the Huancavelica district was purchased by E. E. Fernandini, of Lima, and there appears to be some prospect of a resumption of active mining.

CHANGES IN KNOWN GEOGRAPHICAL DISTRIBUTION IN THE FUTURE

As with most metalliferous ores that have been formed later than the deposition or solidification of their inclosing rocks, the ores of quicksilver are most likely to be found in regions of eruptive activity and complex geologic structure, especially in regions of comparatively late volcanic disturbance. It follows that new deposits are most likely to be discovered within the areas of Tertiary or post-Tertiary volcanic activity, as in the Cordilleran belts of North and South America, the eastern coast of Asia, certain parts of Oceania, and the shores of the Mediterranean. Alaska, Mexico, and the western part of South America seem to offer the greatest possibilities of future productivity, but there is little probability of any important changes in the sources of quicksilver taking place in the near future. The value of a quicksilver deposit can be ascertained as a rule only by mining exploration, and in very few quicksilver mines can any safe estimate be made of “undeveloped” ore. The known facts afford no secure basis for predicting that in the near future some now unimportant district will, within the next ten years, wrest the supremacy in production from Spain, or compete with Austria, Italy, California, or Texas. As regards the principal known sources, it appears that the high-water mark of productivity in California has long been passed, although the mines are still capable of increasing their present production under sufficient stimulus. The Italian output has been increasing of late years, but whether this represents the discovery of new ore bodies or indicates a longer life for the Monte Amiata district is uncertain. A permanent improvement in the political conditions in Mexico, with a continuance of the present, or higher, prices, would probably lead to a notable increase in yield from that country. There is some probability also that Peru may again become an important source of quicksilver.

CHANGES IN PRACTICE

The quicksilver industry is less likely to be modified by changes in mining methods than by improvements in metallurgy. Although very simple in principle, the treatment of quicksilver ores, owing to the mobility and elusiveness of the metal both in the liquid and vaporized condition, is beset with many practical difficulties.

Coarsely broken ore is generally treated in various types of simple shaft furnaces, the fuel being either mixed with the charge or burned in a firebox. Finely broken or pulverulent ore, however, such as forms the larger part of the material from most quicksilver mines, requires different treatment. In Europe the common type of furnace for fine ore is the Spirek and in the United States the Scott-Hütner, or, as more commonly called, the Scott furnace. In both, the ore descends by gravity over tiles of fire-clay so shaped and placed as to permit the flame to pass back and forth through passages under tiles, the passageways or flues being formed partly by the tiles and partly by the ore itself. From the furnace the mercury-laden vapors are conducted through a series of condensing chambers of brick, iron, wood, or other material, in which the metal collects.

When intelligently operated, the Scott furnace is remarkably economical and efficient; but its construction is expensive and requires specially skilled masons. Moreover the furnace is difficult to repair, and once erected can not be moved. These are serious disadvantages to the man of small capital who is developing a new mine, and he usually has to fall back on retorts which are expensive to operate and are unsatisfactory except for relatively small quantities of rich ore.

Of late years attempts have been made in California and Texas to use slightly modified rotary cement-kilns for treating quicksilver ores. This innovation is promising and seems likely to prove successful. Such a furnace, although it may not displace the Scott under some conditions, does not require elaborate masonry structure, and its use may lead to a considerably increased production from the smaller mines.

The condensing systems used with quicksilver furnaces differ greatly and at no two mines in the United States are they identical. The brick condensing chambers formerly so extensively used with the Scott furnace are expensive to build; also the bricks are poor conductors of heat and absorb large quantities of quicksilver. The recent tendency in California has been to replace the brick chambers with large boxes or cylindrical tanks of wood. European practice, followed by one mine in Oregon and one in Texas, favors condensers constructed of vitrified earthenware pipe. The whole question of quicksilver condensation calls for study and skillful experiment. The establishment of a standard of practice would increase production by elimination of much of the loss and discouragement that come from inefficient individual efforts to collect the mercury from the furnace vapors and gases in the most complete and economical way.

POLITICAL CONTROL

The quicksilver industry offers two conspicuous examples of the direct political control of mineral resources. The Almaden mine, whose output is such as in normal times to determine the market for quicksilver, has been owned and worked by the Spanish government since 1645, and the Idria mine up until the close of the war was owned by the Austro-Hungarian government.

The Spanish government, on the basis of competitive proposals, contracts with the successful bidder for the sale of the quicksilver for periods of ten years. For a number of successive periods the contract has been awarded to the Rothschilds of London, the present one dating from June 1, 1912. The contractors bind themselves to sell, in London, the greatest possible quantity of quicksilver, which they take f.o.b. at the reduction plant at Almaden, at prices above 7 pounds per flask, They receive a commission of 1¹⁄₄ per cent. of the amount of the sale; 6 shillings for each flask shipped from Spain to London; and 10 per cent. of the amount by which the sales price exceeds 8 pounds 2 shillings per flask. The Spanish government reserves from the operation of this contract 500 flasks[144] annually for the national requirements of Spain. By this arrangement, although the mine is owned by Spain, the market has been controlled in London. During the war the sale of Almaden mercury was taken over by the Admiralty through Messrs. Rothschild. The quantity received in London from Almaden in 1917 was about 25,000 flasks.

[144] Increased to 10,000 flasks in 1919.

The Konia mine, in Asia Minor, reverted to the Turkish government in 1912, but its output, as previously noted, is inconsiderable.

The quicksilver mines of the Monte Amiata district, Italy, although less obviously illustrative of political control than those just mentioned, should perhaps be referred to in the present connection. German capital has been dominant in their development in the late years before the war, and the most productive mines are credibly reported to have been owned wholly or in part by the German Emperor. With the entry of Italy into the war they were seized by the Italian government. The Italian mines produced about 28,000 flasks, of which from 12,000 to 15,000 flasks were purchased by the British Admiralty.

COMMERCIAL CONTROL

Under present practice the reduction of quicksilver ores is almost invariably at the mine, both mine and reduction works being under the same ownership. They must therefore be considered together for the purpose of the present inquiry.

The most conspicuous example of commercial control is that exercised by the Rothschilds of London, who do not own the resources that give them this pre-eminence. The yield of the remarkably rich Almaden mine, whose annual output surpasses that of any other mine and in 1916 exceeded that of any country except Spain (whose ore, even when carelessly worked, yields quicksilver at low cost, and whose known reserves are large), enables the Rothschilds, in time of peace and subject to the minimum fixed price in their contract, to determine the price at which quicksilver shall be sold in the world’s markets. Another but much smaller factor in making London the leading quicksilver mart of the world is the control by British capital of the principal mines in the Oviedo district, in northern Spain.

In the United States, the country which ranks next to Spain as a producer of quicksilver, the mines are all owned by corporations or individuals, and so far as known, there is at present no formal combination or understanding between these owners to control output or sales. Some years ago most of the leading producers in California formed the Eureka company, which acted as selling agent and to some extent was able to control prices. Often referred to by those outside of it as the “quicksilver trust,” this organization was abandoned after a brief existence. The firm of Haas Brothers, of San Francisco (distinct from Haas Brothers, of New York), took a leading part in the Eureka company, and since its dissolution has fulfilled many of the functions that the company was to perform. The firm owns stock in the leading mine on the Pacific Coast and acts as selling agents for the New Idria Quicksilver Mining Co., whom it charges 1 per cent.[145], whereas it charges others 2¹⁄₂ per cent. It also buys the metal for itself, usually from the smaller producers, at prices generally much below the current market quotation, and is to supply operators with empty flasks, but only on condition that Haas Brothers shall buy the product or sell it on commission. Other brokers who handle important quantities of quicksilver on the Pacific Coast are Atkins, Kroll & Co., and the Braun-Knecht-Hiemann Co., both of San Francisco. So far as known these two firms have no ownership in quicksilver mines and sell only on commission.

[145] This connection is reported to have been broken in 1919.

The quicksilver mines in Texas are owned by American citizens or American corporations. The ore from each is independently worked and the quicksilver is sold by the individual producers.

The mercury deposits of Mexico are owned, as far as is known, by native Mexicans. British capital is probably interested in some of the larger mines. The formerly productive quicksilver mines at Huancavelica, Peru, have been purchased by E. E. Fernandini, of Lima, and may again contribute to the world’s supply.

So far as known to the writer of this article, patents, secret processes or trade agreements play no part in the control of quicksilver resources.

During the war Germany and her allies controlled the quicksilver deposits of Australia, Serbia, Turkey and probably European Russia. Only the Idria deposit, and perhaps the Zips deposit, in Austria, are important, and the available annual supply for the Teutonic allies was probably 25,000 to 30,000 flasks. The Entente allies controlled the deposits of the United States, yielding about 36,000 flasks annually; of Italy, yielding about 28,000 flasks; and controlled, although they did not own, the deposits of neutral Spain, yielding from 30,000 to 41,000 flasks annually. The Chinese mercury deposits were possibly drawn upon to some extent by Japan, who, like Britain and France, has no deposits of her own that are worth mentioning.

SUMMARY

The chief uses of mercury and mercury compounds, in general order of decreasing importance, are as follows: In the manufacture of drugs and chemicals, including calomel, corrosive sublimate, and glacial acetic acid; as a detonator for high explosives; as vermilion pigment; in electrical apparatus, thermostats, gas governors, and other appliances; in the amalgamation of gold and silver ores; in anti-fouling marine paint; in compounds to prevent boiler scale; in cosmetics; and in dental amalgam. There are comparatively few applications of mercury where a substitute could not be employed, although the substitute might not be as economical or as satisfactory.

In general the ores of quicksilver do not extend to great depths and show on the whole a close association with Tertiary and Quaternary igneous rocks that have not been subjected to long and deep erosion. There are some notable exceptions, however, to these generalizations. New deposits of mercury are most likely to be discovered on the eastern coast of Asia, in certain parts of Oceania, on the shores of the Mediterranean, or in the Cordilleran belts of North and South America. The known facts afford no secure basis for predicting that there will be within the next ten years any marked shift from the present main sources of supply to some newly discovered deposit.

The richest mercury deposits are at Almaden, central Spain; at Idria, Austria-Hungary; and in the Monte Amiata district of Italy. Other productive deposits are situated near Oviedo and Granada, Spain; in the Donetz coal basin, Russia; near Aidin, Turkey; in the province of Kweichow, China; in Oregon, California, Nevada, and Texas; in San Luis Potosi, Guerrero, and Durango, Mexico; and in Peru. Many deposits at present unproductive are known in other parts of the world.

The political control of the quicksilver deposits corresponds for the most part with geographic location. The rich deposits of Almaden, in Spain, and Idria, in old Austria-Hungary, are government-owned. The Spanish government, on the basis of competitive proposals, contracts with the successful bidder for the sale of the quicksilver for a period of ten years. The contract has been awarded to the Rothschilds of London for a number of successive periods. This control of the output of the Spanish mines gives the Rothschilds a control of the world’s quicksilver market. The Spanish government reserves a sufficient number of flasks annually for the national requirements of Spain. The Konia mine, in Asia Minor, has been the property of the Turkish government since 1912. It is believed that the most productive mines of the Monte Amiata district, Italy, were owned wholly or in part by the German Emperor; with the entry of Italy into the war they were seized by the Italian government. The mines of the United States are all controlled by corporations or individuals. It is believed that the mines of Mexico are owned by Mexican citizens, although British capital may be invested in some of them. The mines at Huancavelica, Peru, have been purchased by Señor E. E. Fernandini, of Lima.