Chapter 6

The statistics of this report are divided into two sections: First, the discoveries and finds of precious stones in the United States and the mineral specimens sold for museums and private collections or for bric-a-brac purposes; second, the diamond cutting industry.

DISCOVERIES OF PRECIOUS STONES.

Up to the present time there has been very little mining for precious or semi-precious stones in the United States, and then only at irregular periods. It has been carried on during the past few years at Paris, Maine; near Los Cerrillos, New Mexico; in Alexander County, North Carolina, from 1881 until 1888; and on the Missouri River near Helena, Montana, since the beginning of 1890. True beryls and garnets have been frequently found as a by-product in the mining of mica, especially in Virginia and North Carolina. Some gems, such as the chlorastrolite, thomsonite, and agates of Lake Superior, are gathered on beaches, where they have fallen from rock which has gradually disintegrated by weathering and wave action.

_Diamond._--A very limited number of diamonds have been found in the United States. They are met with in well-defined districts of California, North Carolina, Georgia, and recently in Wisconsin, but up to the present time the discoveries have been rare and purely accidental.

_Sapphire._--Of the corundum gems (sapphire, ruby, and other colored varieties), no sapphires of fine blue color and no rubies of fine red color have been found. The only locality which has been at all prolific is the placer ground between Ruby and Eldorado bars, on the Missouri River, sixteen miles east of Helena, Montana. Here sapphires are found in glacial auriferous gravels while sluicing for gold, and until now have been considered only a by-product. Up to the present time they have never been systematically mined. In 1889 one company took the option on four thousand acres of the river banks, and several smaller companies have since been formed with a view of mining for these gems alone or in connection with gold. The colors of the gems obtained, although beautiful and interesting, are not the standard blue or red shades generally demanded by the public.

At Corundum Hill, Macon County, North Carolina, about one hundred gems have been found during the last twenty years, some of good blue color and some of good red color, but none exceeding $100 in value, and none within the past ten years.

_Beryl Gems._--Of the beryl gems (emerald, aquamarine, and yellow beryl) the emerald has been mined to some extent at Stony Point in Alexander County, North Carolina, and has also been obtained at two other places in the county. Nearly everything found has come from the Emerald and Hiddenite mines, where during the past decade emeralds have been mined and cut into gems to the value of $1,000, and also sold as mineralogical specimens to the value of $3,000; lithia emerald, or hiddenite, to be cut into gems, $8,500, and for mineralogical specimens, $1,500; rutile, cut and sold as gems, $150, and as specimens, $50; and beryl, cut and sold as gems, $50.

At an altitude of 14,000 feet, on Mount Antero, Colorado, during the last three years, material has been found which has afforded $1,000 worth of cut beryls. At Stoneham, Maine, about $1,500 worth of fine aquamarine has been found, which was cut into gems.

At New Milford, Connecticut, a property was extensively worked from October, 1885, to May, 1886, for mica and beryl. The beryls were yellow, green, blue, and white in color, the former being sold under the name of "golden beryl." No work has been done at the mine since then. In 1886 and 1887 there were about four thousand stones cut and sold for some $15,000, the cutting of which cost about $3,000.

_Turquoise._--This mineral, which was worked by the Aztecs before the advent of the Spaniards, and since then by the Pueblo Indians, and largely used by them for ornament and as an article of exchange, is now systematically mined near Los Cerrillos, New Mexico. Its color is blue, and its hardness is fully equal to that of the Persian, or slightly greater, owing to impurities, but it lacks the softness of color belonging to the Persian turquoise.

From time immemorial this material has been rudely mined by the Indians. Their method is to pour cold water on the rocks after previously heating them by fires built against them. This process generally deteriorates the color of the stone to some extent, tending to change it to a green. The Indians barter turquoise with the Navajo, Apache, Zuni, San Felipe, and other New Mexican tribes for their baskets, blankets, silver ornaments, and ponies.

_Garnet and Olivine (Peridot)._--The finest garnets and nearly all the peridots found in the United States are obtained in the Navajo Nation, in the northwestern part of New Mexico and the northeastern part of Arizona, where they are collected from ant hills and scorpion nests by Indians and by the soldiers stationed at adjacent forts. Generally these gems are traded for stores to the Indians at Gallup, Fort Defiance, Fort Wingate, etc., who in turn send them to large cities in the East in parcels weighing from half an ounce to thirty or forty pounds each. These garnets, which are locally known as Arizona and New Mexico rubies, are the finest in the world, rivaling those from the Cape of Good Hope. Fine gems weighing from two to three carats each and upward when cut are not uncommon. The peridots found associated with garnets are generally four or five times as large, and from their pitted and irregular appearance have been called "Job's tears." They can be cut into gems weighing three to four carats each, but do not approach those from the Levant either in size or color.

_Gold Quartz._--Since the discovery of gold in California, compact gold quartz has been extensively used in the manufacture of jewelry, at one time to the amount of $100,000 per annum. At present, however, the demand has so much decreased that only from five to ten thousand dollars' worth is annually used for this purpose.

In addition to the minerals used for cabinet specimens, etc., there is a great demand for making clocks, inkstands, and other objects.

_Quartz._--During the year 1887 about half a ton of rock crystal, in pieces weighing from a few pounds up to one hundred pounds each, was found in decomposing granite in Chestnut Hill township, Ashe County, North Carolina. One mass of twenty and one-half pounds was absolutely pellucid, and more or less of the material was used for art purposes. This lot of crystal was valued at $1,000.

In Arkansas, especially in Garland and Montgomery Counties, rock crystals are found lining cavities of variable size, and in one instance thirty tons of crystals were found in a single cavity. These crystals are mined by the farmers in their spare time and sold in the streets of Hot Springs, their value amounting to some $10,000 annually. Several thousand dollars' worth are cut from quartz into charms and faceted stones, although ten times that amount of paste or imitation diamonds are sold as Arkansas crystals.

Rose quartz is found in the granitic veins of Oxford County, Maine, and in 1887, 1888, and 1889 probably $500 worth of this material was procured and worked into small spheres, dishes, charms, and other ornamental objects.

The well-known agatized and jasperized wood of Arizona is so much richer in color than that obtained from any other known locality that, since the problem of cutting and polishing the large sections used for table tops and other ornamental purposes was solved, fully $50,000 worth of the rough material has been gathered and over $100,000 worth of it has been cut and polished. This wood, which was a very prominent feature at the Paris Exposition, promises to become one of our richest ornamental materials.

Chlorastrolite in pebbles is principally found on the inside and outside shores of Rock Harbor, a harbor about eight miles in length on the east end of Isle Royale, Lake Superior, where they occur from the size of a pin head to, rarely, the size of a pigeon's egg. When larger than a pea they frequently are very poor in form or are hollow in fact, and unfit for cutting into gems. They are collected in a desultory manner, and are sold by jewelers of Duluth, Petoskey, and other cities, principally to visitors. The annual sale ranges from $200 to $1,000.

Thomsonite in pebbles occurs with the chlorastrolite at Isle Royal, but finer stones are found on the beach at Grand Marais, Cook County, Minnesota. Like the chlorastrolites, they result from the weathering of the amygdaloid rock, in which they occur as small nodules, and in the same manner are sold by jewelers in the cities bordering on Lake Superior to the extent of $200 to $1,000 worth annually.

THE DIAMOND CUTTING INDUSTRY.

In New York there are sixteen firms engaged in cutting and recutting diamonds, and in Massachusetts there are three. Cutting has also been carried on at times in Pennsylvania and Illinois, but has been discontinued. The firms that were fully employed were generally the larger ones, whose business consisted chiefly in repairing chipped or imperfectly cut stones or in recutting stones previously cut abroad, which, owing to the superior workmanship in command here, could be recut at a profit, or in recutting very valuable diamonds when it was desired, with the certainty that the work could be done under their own supervision, thus guarding against any possible loss by exchange for inferior stones.

The industry employed 236 persons, of whom 69 were under age, who received $148,114 in wages. Of the 19 establishments, 16 used steam power. The power is usually rented. Foot power is only used in one establishment. Three of the firms are engaged in shaping black diamonds for mechanical purposes, for glass cutters and engravers, or in the manufacture of watch jewels.

The diamonds used in this industry are all imported, for, as already stated, diamonds are only occasionally found in the United States.

The importation of rough and uncut diamonds in 1880 amounted to $129,207, in 1889 to $250,187, and the total for the decade was $3,133,529, while in 1883 there were imported $443,996 worth, showing that there was 94 per cent. more cutting done in 1889 than 1880, but markedly more in 1882 and 1883. This large increase of importation is due to the fact that in the years 1882 to 1885 a number of our jewelers opened diamond cutting establishments, but the cutting has not been profitably carried on in this country on a scale large enough to justify branch houses in London, the great market for rough diamonds, where advantage can be taken of every fluctuation in the market and large parcels purchased, which can be cut immediately and converted into cash; for nothing is bought and sold on a closer margin than rough diamonds.

There has been a remarkable increase in the importation of precious stones in this country in the last ten years. The imports from 1870 to 1879, inclusive, amounted to $26,698,203, whereas from 1880 to 1889, inclusive, the imports amounted to $87,198,114, more than three times as much as were imported the previous decade.

* * * * *

SOME EXPERIMENTS ON THE ELECTRIC DISCHARGE IN VACUUM TUBES.[1]

[Footnote 1: From a recent communication made to the Physical Society, London.]

By Prof. J.J. THOMSON, M.A., F.R.S.

The phenomena of vacuum discharges were, he said, greatly simplified when their path was wholly gaseous, the complication of the dark space surrounding the negative electrode and the stratifications so commonly observed in ordinary vacuum tubes being absent. To produce discharges in tubes devoid of electrodes was, however, not easy to accomplish, for the only available means of producing an electromotive force in the discharge circuit was by electromagnetic induction. Ordinary methods of producing variable induction were valueless, and recourse was had to the oscillatory discharge of a Leyden jar, which combines the two essentials of a current whose maximum value is enormous, and whose rapidity of alternation is immensely great.

The discharge circuits, which may take the shape of bulbs, or of tubes bent in the form of coils, were placed in close proximity to glass tubes filled with mercury, which formed the path of the oscillatory discharge. The parts thus corresponded to the windings of an induction coil, the vacuum tubes being the secondary and the tubes filled with the mercury the primary. In such an apparatus the Leyden jar need not be large, and neither primary nor secondary need have many turns, for this would increase the self-induction of the former and lengthen the discharge path in the latter. Increasing self-induction of the primary reduces the E.M.F. induced in the secondary, while lengthening the secondary does not increase the E.M.F. per unit length. Two or three turns (Fig. 1) in each were found to be quite sufficient, and on discharging the Leyden jar between two highly polished knobs in the primary circuit, a plain uniform band of light was seen to pass round the secondary. An exhausted bulb (Fig. 2) containing traces of oxygen was placed within a primary spiral of three turns, and, on passing the jar discharge, a circle of light was seen within the bulb in close proximity to the primary circuit, accompanied by a purplish glow, which lasted for a second or more. On heating the bulb the duration of the glow was greatly diminished, and it could be instantly extinguished by the presence of an electromagnet. Another exhausted bulb (Fig. 3), surrounded by a primary spiral, was contained in a bell jar, and when the pressure of air in the jar was about that of the atmosphere the secondary discharge occurred in the bulb, as is ordinarily the case. On exhausting the jar, however, the luminous discharge grew fainter, and a point was reached at which no secondary discharge was visible. Further exhaustion of the jar caused the secondary discharge to appear outside the bulb. The fact of obtaining no luminous discharge either in the bulb or jar the author could only explain on two suppositions, viz., that under the conditions then existing the specific inductive capacity of the gas was very great, or that a discharge could pass without being luminous. The author had also observed that the conductivity of a vacuum tube without electrodes increased as the pressure diminished until a certain point was reached, and afterward diminished again, thus showing that the high resistance of a nearly perfect vacuum is in no way due to the presence of the electrodes. One peculiarity of the discharges was their local nature, the rings of light being much more sharply defined than was to be expected. They were also found to be most easily produced when the chain of molecules in the discharge were all of the same kind. For example, a discharge could be easily sent through a tube many feet long, but the introduction of a small pellet of mercury in the tube stopped the discharge, although the conductivity of the mercury was much greater than that of the vacuum. In some cases he had noticed that a very fine wire placed within a tube on the side remote from the primary circuit would prevent a luminous discharge in that tube.

* * * * *

THE ELECTRICAL MANUFACTURE OF PHOSPHORUS.

Dr. Readman, at the May meeting of the Glasgow Section of the Society of Chemical Industry, gave a description of the new works and plant which have been erected at Wolverhampton for the manufacture of phosphorus by the Readman-Parker patents. The process consists in decomposing the mixture of phosphoric acid, or acid phosphates and carbon, by the heat of the electric arc embedded in the mass.

* * * * *

LAYING A MILITARY FIELD TELEGRAPH LINE.

The 1st Division of the Royal Engineers, Telegraph Battalion, now encamped at Chevening, close to Lord Stanhope's park, as a summer exercise is engaged in running a military telegraph field line from Aldershot to Chatham. Along the whole of the line the wire is supported on light fir and bamboo poles. The work has been carried out with unusual celerity. From Aldershot to Chevening, a distance of fifty miles, the line was erected in a day and a quarter, or under thirty hours, the detachments employed having worked or marched all night. This is, it is said, the greatest length of telegraph line ever laid within so short a time. The result cannot fail to be useful, for by the new line communication is now established both by telegraph and telephone between Aldershot and Chatham. For laying such telegraph lines to accompany calvary, a light cable is made use of. This is carried on reels on a wheeled cart, and can be laid at the rate of six to seven miles an hour. The Telegraph Battalion of the Royal Engineers comprises two divisions. One is employed in time of peace under the Post Office in the construction and maintenance of postal lines; the other, stationed at Aldershot, is equipped with field telegraph material.--_Daily Graphic._

* * * * *

AN ELECTROSTATIC SAFETY DEVICE.

This device, as shown in the accompanying illustration, is a glass cylinder fixed on an ebonite base, and closed at the top by an ebonite cap. A solid brass rod runs from top to bottom, and near the bottom, and at right angles to it, is fixed a smaller adjustable rod, terminating in a flat head. Opposite to this flat disk there is a brass strip secured to the ebonite cap. From the top of this brass strip hangs a gold or aluminum foil. The foil and strip are placed to earth, and the solid brass rod is connected to the circuit to be protected. Should the difference of potential between the foil and the terminal opposite to it attain more than a certain amount, electrostatic attraction will cause the foil to touch the disk and place the circuit to earth. The apparatus, which is a modification of the Cardew earthing device, is constructed by Messrs. Drake & Gorham, of Victoria Street.--_The Electrician_.

* * * * *

EXPERIMENTS WITH HIGH TENSION ALTERNATING CURRENTS.

Messrs. Siemens and Halske, of Berlin, recently invited the members of the Elektrotechnische Verein of that city to their works to witness the demonstration of a series of experiments on alternating currents under a pressure of 20,000 volts. In order to show that the desired pressure was really _en evidence_, the high tension was conducted through a pair of wires of only 0.2 mm. diameter to a battery of 200 100-volt incandescent lamps, all connected up in series. An ordinary Siemens electric light cable was inserted, and broke down at a pressure of some 15,000 volts.

At the end of the meeting a few experiments on the formation of the arc under this enormous pressure were shown. The sparking distance varied considerably, according to the shape of the electrodes. At 20,000 volts a spark jumped from a ball to a ball about 10 millimeters, while between two points a sparking distance of 30 millimeters, and sometimes even more, was reached. This arc is shown half size in the accompanying engraving.

The arc which followed the jumping over of a spark made a loud humming and clapping noise, and flapped about, being easily carried away by the slightest draught. The arc could be drawn out horizontally to something like 100 millimeters distance between the electrodes, and even to a distance of 150 millimeters, when carbon pencils were used as electrodes, but it always remained standing up in a point. --_Electrical Engineer._

* * * * *

THE RELATION OF BACTERIA TO PRACTICAL SURGERY.[1]

[Footnote 1: The address in surgery delivered before the Medical Society of the State of Pennsylvania, June 4, 1890.]

By JOHN B. ROBERTS, A.M., M.D., Professor of Surgery in the Woman's Medical College and in the Philadelphia Polyclinic.

The revolution which has occurred in practical surgery since the discovery of the relation of micro-organisms to the complications occurring in wounds has caused me to select this subject for discussion. Although many of my hearers are familiar with the germ theory of disease, it is possible that it may interest some of them to have put before them in a short address a few points in bacteriology which are of value to the practical surgeon.

It must be remembered that the groups of symptoms which were formerly classed under the heads "inflammatory fever," "symptomatic fever," "traumatic fever," "hectic fever," and similar terms, varying in name with the surgeon speaking of them, or with the location of the disease, are now known to be due to the invasion of the wound by microscopic plants. These bacteria, after entering the blood current at the wound, multiply with such prodigious rapidity that the whole system gives evidence of their existence. Suppuration of wounds is undoubtedly due to these organisms, as is tubercular disease, whether of surgical or medical character. Tetanus, erysipelas, and many other surgical conditions have been almost proved to be the result of infection by similar microscopic plants, which, though acting in the same way, have various forms and life histories.

A distinction must be made between the "yeast plants," one of which produces thrush, and the "mould plants," the existence of which, as parasites in the skin, gives rise to certain cutaneous diseases. These two classes of germs are foreign to the present topic, which is surgery; and I shall, therefore, confine my remarks to that group of vegetable parasites to which the term bacteria has been given. These are the micro-organisms whose actions and methods of growth particularly concern the surgeon. The individual plants are so minute that it takes in the neighborhood of ten or fifteen hundred of them grouped together to cover a spot as large as a full stop or period used in punctuating an ordinary newspaper. This rough estimate applies to the globular and the egg-shaped bacteria, to which is given the name "coccus" (plural, cocci). The cane or rod shaped bacteria are rather larger plants. Fifteen hundred of these placed end to end would reach across the head of a pin. Because of the resemblance of these latter to a walking stick they have been termed bacillus (plural, bacilli).

The bacteria most interesting to the surgeon belong to the cocci and the bacilli. There are other forms which bacteriologists have dubbed with similar descriptive names, but they are more interesting to the physician than to the surgeon. Many micro-organisms, whether cocci, bacilli, or of other shapes, are harmless, hence they are called non-pathogenic, to distinguish them from the disease-producing or pathogenic germs.

As many trees have the same shape and a similar method of growing, but bear different fruits--in the one case edible and in the other poisonous--so, too, bacteria may look alike to the microscopist's eye, and grow much in the same way, but one will cause no disease, while the other will produce perhaps tuberculosis of the lungs or brain.