Chapter 5

This loss may be caused by the expectoration and night-sweats, or it may also be produced by defective mineral nutrition, either from deficient supply in the food, or from non assimilation. But, whatever causes this deficiency, it is universally acknowledged that it is essential the food should contain a proper supply of the mineral elements. If the body is well nourished, the resisting force of the system is raised. Professor Koch and others, who accept the germ theory of disease to its fullest extent, state that the minute organisms of tubercular disease do not occur in the tissues of healthy bodies, and that when introduced into a living body their propagation and increase are greatly favored by a low state of the general health.

Dr. Pavy, F.R.S., showed in his address on the "Dietetics of Bread" that in white flour, instead of obtaining the 23 parts of mineral matter to 100 parts of nitrogenous matter--which is the accepted ratio of a standard diet--we should only get 4.20 parts of mineral matter. Professor Church states that 1 lb. of white flour has only 49 grains of mineral matter, while 1 lb. of whole wheat meal has 119 grains. Whole wheat meal, besides containing other essential mineral elements, has double the amount of lime, and nearly three times the amount of phosphoric acid; so that if defective mineral nutrition in any way predisposes to consumption, the adoption of wheat meal prepared in a digestible and palatable form is of primary importance for those who are unable to obtain the phosphates from high-priced animal foods.

Wheat meal has also great advantages for those who are able to afford animal food, for, as Dr. Pavy stated, "It acts as a greater stimulant to the digestive organs."

It is probably due to this stimulating property of wheat meal that people who have adopted it find they can digest animal fat much better than previously. If this is corroborated by general experience, it may be of great benefit in aiding the system to resist tendencies toward consumption and scrofula, for these diseases are generally accompanied by loss of the power of assimilating fat. It is believed that a deficiency of oleaginous matter is a predisposing cause of tuberculous disease. An important prophylactic, therefore, against such maladies, would be a general increase in the use of butter and other fatty foods.

There is such good reason to believe that a low state of nutrition favors the development of tuberculous disease, that parents cannot be too strongly urged to provide their children with a proper supply of healthy, nourishing, and pure food (under which term must, of course, be included pure air and pure water), for by so doing they may often arrest consumptive tendencies, and thus would be diminished the ravages of that fatal disease which, when once established, is "the despair of the physician, and the terror of the public."

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THE NEW YORK FISH COMMISSION PONDS AT CALEDONIA.

The capacity of the New York State fish farm at Caledonia is 6,000,000 fry a year. The recently issued report of the fish commissioners says that this year the ponds will be worked to their full capacity.

The supply of spawn has been greater than could be hatched there, and supplies were sent to responsible persons in every State in the Union to be experimented with. At the date of issuing the report the supply of stock fish at the hatchery embraced, it was estimated, a thousand salmon trout, of weights ranging from four to twelve pounds; ten thousand brook trout, from half a pound to two pounds in weight; thirty thousand California mountain trout, weighing from a quarter of a pound to three pounds; forty-seven hundred rainbow trout, of from a quarter of a pound to two pounds' weight; and a large number of hybrids produced by crossing and interbreeding of different members of the salmon tribe. In this connection reference is made to the interesting fact that hybrids of the fish family are not barren. Spawners produced by crossing the male brook trout with the female salmon trout cast 72,000 eggs last fall, which hatched as readily as the spawn of their progenitors. The value of the stock of breeding fish at the hatchery is estimated at $20,000.

The hatch of salmon trout this season was not far from 1,200,000, and these will be distributed chiefly in the large lakes of the interior. About a million little brook trout were produced. The commission doubts whether much benefit has resulted from attempting to stock small streams that have once been good trout waters, but the temperature of which has been changed by cutting away the forest trees that overhung them. The best results have been attained where the waters are of considerable extent, especially those in and bordering on the wilderness in the northern part of the State. The experiments with California trout, have been very successful, and it is found that the streams most suitable for them, are the Hudson, Genesee, Mohawk, Moose, Black, and Beaver rivers, and the East and West Canada creeks. The commission hopes to hatch 6,000,000 or 8,000,000 shad this season at a cost of about $1,000. Concerning German carp, the commissioners find that the water at Caledonia is too cold for this fish, but think that carp would do well in waters further south.

The commission awaits a more liberal appropriation of money before beginning the work of hatching at the new State fish farm at Cold Spring, on the north side of Long Island, thirty miles out from Brooklyn.

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MIOCENE MAN.

Grant Allen, an English evolutionist, gives this imaginary picture of our supposed ancestor: "We may not unjustifiably picture him to ourselves as a tall and hairy creature, more or less erect, but with a slouching gait, black faced and whiskered, with prominent, prognathous muzza, and large, pointed canine teeth, those of each jaw fitted into an interspace in the opposite row. These teeth, as Mr. Darwin suggests, were used in the combats of the males. His forehead was no doubt low and retreating, with bony bosses underlying the shaggy eyebrows, which gave him a fierce expression, something like that of the gorilla. But already, in all likelihood, he had learned to walk habitually erect, and had begun to develop a human pelvis, as well as to carry his head more straight on his shoulders. That some such animal must have existed seems to me an inevitable corollary from the general principles of evolution and a natural inference from the analogy of other living genera."

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GOULIER'S TUBE-GAUGE.

As well known, the method by which glass barometer tubes are made gives them variable calibers. Not only do the different tubes vary in size, but even the same tube is apt to have different diameters throughout its length, and its sections are not always circular. Manufacturers of barometers often have need to know exactly the dimensions of the sections of these tubes, and to ascertain whether they are equal throughout a certain length of tube, and this is especially necessary in those instruments in which the surfaces of the sections of the reservoir and tube must bear a definite ratio to one another. Having ascertained that no apparatus existed for measuring the caliber of these and anolagous tubes, and that manufacturers had been accustomed to make the measurements by roundabout methods, Colonel Goulier has been led to devise a small apparatus for the purpose, and which is shown in the accompanying cuts.

The extremity of a brass tube, T, 0.5 to 0.6 of a meter in length and smaller in diameter than the tube to be gauged, is cut into four narrow strips a few centimeters in length. The extremity of each of these strips is bent toward the axis of the tube. Two of them, m and m', opposite each other are made very flexible, and carry, riveted to their extremities, two steel buttons, the heads of which, placed in the interior, have the form of an obtuse quoin with rounded edge directed perpendicular to the tube's axis. The other extremities of these buttons are spherical and polished and serve as caliper points in the operation of measuring. These buttons are given a thickness such that when the edges of their heads are in contact, the external diameter of the tube exceeds the distance apart of the two calibrating points by more than one millimeter. But such distance apart is increased within certain limits by inserting between the buttons a German silver wedge, L, carried by a rod, t, which traverses the entire tube, and which is maneuvered by a head, B, fixed to its extremity. This rod carries a small screw, v, whose head slides in a groove, r, in the tube, so as to limit the travel of the wedge and prevent its rotation. Beneath the head, B, the rod is filed so as to give it a plane surface for the reception of a divided scale. A corresponding slit in the top of the tube carries the index, I, of the scale. The principal divisions of the scale have been obtained experimentally, and traced opposite the index when the calibrating points were exactly 7, 8, 9 etc., millimeters apart. As the angle of the wedge is about one tenth, the intervals between these divisions are about one centimeter. These intervals are divided into ten parts, each of which corresponds to a variation in distance of one tenth of a millimeter.

To calibrate a glass tube with this instrument, the tube is laid upon the table, the gauge is inserted, and the buttons are introduced into the section desired. The flat side of the head, B, being laid on the table, arranges, as shown in the figure, the buttons perpendicular to it. Then the measuring wedge is introduced until a stoppage occurs through the contact of the buttons with the sides of the tube. Finally, their distance apart is read on the scale. Such distance apart will be the measure of a diameter or a chord of the tube's section, according as the buttons have been kept in the diametral plane or moved out of it. In order that the operator shall not be obliged to watch the position of the line of calibrating buttons in obtaining the diameter, the following arrangement has been devised: The sides of the measuring wedge are filed off to a certain angle, and the ends of the corresponding strips, d and d', are bent inward in the form of hooks, whose extremities always rest on the faces of the directing wedges. The length of these hooks and the angle of the wedge are such that the distance apart of the rounded backs of the directing strips is everywhere less, by about one-thirtieth, than that of the calibrating buttons. From this it will be seen that if the wedge be drawn back, and inserted again after the tube has been turned, we shall measure the diameter that is actually vertical. It becomes possible, then, to determine the greatest and smallest diameters in a few minutes; and, supposing the section elliptical, its area will be obtained by multiplying the product of these two diameters by pi/4.

From the description here given it will be seen that Colonel Goulier's apparatus is not only convenient to use, but also permits of obtaining as accurate results as are necessary. Two sizes of the instrument are made, one for diameters of from 7 to 10.5 mm., and the other for those of from 10 to 15.5 mm. It is the former of these that is shown, of actual size, in the cuts.

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SOLDERING WITHOUT AN IRON.

The following method for soldering without the use of a soldering iron is given in the _Techniker_:

The parts to be joined are made to fit accurately, either by filing or on a lathe. The surfaces are moistened with the soldering fluid, a smooth piece of tin foil laid on, and the pieces pressed together and tightly wired. The article is then heated over the fire or by means of a lamp until the tin foil melts. In this way two pieces of brass can be soldered together so nicely that the joint can scarcely be found.

With good soft solder, nearly all kinds of soldering can be done over a lamp without the use of a "copper." If several piaces have to be soldered on the same piece, it is well to use solder of unlike fusibility. If the first piece is soldered with fine solder composed of 2 parts of lead, 1 of tin, and 2 of bismuth, there is no danger of its melting when another place near it is soldered with bismuth solder, made of 4 parts of lead, 4 of tin, and 1 of bismuth, for their melting points differ so much that the former will not melt when the latter does. Many solders do not form any malleable compounds.

In soldering together brass, copper, or iron, hard solder must be employed; for example, a solder made of equal parts of brass and silver (!). For iron, copper, or brass of high melting point, a good solder is obtained by rolling a silver coin out thin, for it furnishes a tenacious compound, and one that is not too expensive, since silver stretches out well. Borax is the best flux for hard soldering. It dissolves the oxides which form on the surface of the metal, and protects it from further oxidation, so that the solder comes into actual contact with the surfaces of the metal. For soft soldering, the well-known fluid, made by saturating equal parts of water and hydrochloric acid with zinc, is to be used. In using common solder rosin is the cheapest and best flux. It also has this advantage, that it does not rust the article that it is used on.--_Deutsche Industrie Zeitung_.

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WORKING COPPER ORES AT SPENCEVILLE.

From a letter in the Grass Valley _Tidings_ we make the following extracts:

The Spenceville Copper Mining Company have 43 acres of copper-bearing ground and 100 acres of adjoining land, which was bought for the timber. There are a hoisting works, mill, roasting sheds, and leaching vats on the ground, and they cover several acres.

On going around with Mr. Ellis, the first place we came to was the mine proper, which is simply an immense opening in the ground covering about one half of an acre, and about 80 feet deep. It has an incline running down into it, by which the ore is hoisted to the surface. Standing on the brink of this opening and looking down, we could see the men at work, some drilling, others filling and running the cars to the incline to be hoisted to the surface.

The ore is found in a sort of chloritic slate and iron pyrites which follow the ledge all around. The ore itself is a fine-grained pyrite, with a grayish color, and it is well suited by its sulphur and low copper contents, as well as by its properties for heap roasting. In heap roasting, the ore is hand-broken by Chinamen into small lumps before being hoisted to the surface. From the landing on the surface it is run out on long tracks under sheds, dumped around a loose brick flue and on a few sticks of wood formed in the shape of a V, which runs to the flues to give a draught. Layers of brush are put on at intervals through the pile. The smaller lumps are placed in the core of the heap, the larger lumps thrown upon them, and 40 tons of tank residues thrown over all to exclude excess of air; 500 lb. of salt is then distributed through the pile, and it is then set afire. After well alight the draught-holes are closed up, and the pile is left to burn, which it does for six months. At the expiration of that time the pile is broken into and sorted, the imperfectly roasted ore is returned to a fresh roast-heap, and the rest trammed to the

LEACH-VATS.

These are 50 in number, 10 having been recently added. The first 40 are four feet by six feet and four feet deep, the remaining 10 twice as large. About two tons of burnt ore is put in the small vats (twice as much in the larger ones), half the vats being tilled at one time, and then enough cold water is turned in to cover the ore. Steam is then injected beneath the ore, thus boiling the water. After boiling for some time, the steam is turned off and the water allowed to go cold. The water, which after the boiling process turns to a dark red color, is then drawn off. This water carries the copper in a state of solution. The ore is then boiled a second time, after which the tank residues are thrown out and water kept sprinkling over them. This water collects the copper still left in the residues, and is then run into a reservoir, and from the reservoirs still further on into settling tanks, previous to

PRECIPITATION,

and is then conducted through a system of boxes filled with scrap iron, thus precipitating the copper.

The richer copper liquors which have been drawn from the tanks fire not allowed to run in with that which comes from the dump heaps. This liquor is also run into settling tanks, and from them pumped into four large barrels, mounted horizontally on friction rollers, to which a very slow motion is given. These barrels are 18 feet long and six feet six inches deep outside measure. They are built very strongly, and are water-tight. Ten tons of scrap iron are always kept in each of these barrels, which are refilled six times daily, complete precipitation being effected in less than four hours. Each barrel is provided with two safety valves, inserted in the heads, which open automatically to allow the escape of gas and steam. The precipitation of the copper in the barrels forms copper cement. This cement is discharged from the barrels on to screens which hold any lumps of scrap iron which may be discharged with the cement. It is then dried by steam, after which it is conveyed into another tank, left to cool, and then placed in bags ready for shipment, as copper cement. The building in which the liquor is treated is the mill part of the property, from which they send out 42 tons monthly of an average of 85 per cent, of copper cement, this being the average yield of the mine.

There are 23 white men and 40 Chinamen employed at the mine and the mill. There are also several wood choppers, etc., on the company's pay-roll. Eight months' supply of ore is always kept on hand, there now being 12,000 tons roasting. The mine is now paying regular monthly dividends, and everything argues well for the continuance of the same.

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SIR WILLIAM THOMSON'S PILE.

The Thomson pile, which is employed with success for putting in action the siphon recorder, and which is utilized in a certain number of cases in which an energetic and constant current is needed, is made in two forms. We shall describe first the one used for demonstration. Each element of this (Fig. 1) consists of a disk of copper placed at the bottom of a cylindrical glass vessel, and of a piece of zinc in the form of a grating placed at the upper part, near the surface of the solution. A glass tube is placed vertically in the solution, its lower extremity resting on the copper. Into this tube are thrown some crystals of sulphate of copper, which dissolve in the liquid, and form a solution of a greater density than that of the zinc alone, and which, consequently, cannot reach the zinc by diffusion. In order to retard the phenomenon of diffusion, a glass siphon containing a cotton wick is placed with one of its extremities midway between the copper and zinc, and the other in a vessel outside the element, so that the liquid is sucked up slowly nearly to its center. The liquid is replaced by adding from the top either water or a weak solution of sulphate of zinc.

The greater part of the sulphate of copper that rises through the liquid by diffusion is carried off by the siphon before reaching the zinc, the latter being thus surrounded with an almost pure solution of sulphate of copper having a slow motion from top to bottom. This renewal of the liquid is so much the more necessary in that the saturated solution of sulphate of copper has a density of 1.166, and the sulphate of zinc one of 1.445, There would occur, then, a mixture through inversion of densities if the solution were allowed to reach a too great amount of saturation, did not the siphon prevent such a phenomenon by sucking up the liquid into the part where the mixture tends to take place. The chemical action that produces the current is identical with that of the Daniell element.

In its application, this pile is considerably modified in form and arrangement. Each element (Fig 2) consists of a flat wooden hopper-shaped trough, about fifty centimeters square, lined with sheet lead to make it impervious. The bottom is covered with a sheet of copper and above this there is a zinc grate formed of closely set bars that allow the liquid to circulate. This grate is provided with a rim which serves to support a second similar element, and the latter a third, and soon until there are ten of the elements superposed to form series mounted for tension. The weight of the elements is sufficient to secure a proper contact between the zinc and copper of the elements placed beneath them, such contact being established by means of a band of copper cut out of the sheet itself, and bent over the trough.

On account of the large dimensions of the elements, and the proximity of the two metals, a pile is obtained whose internal resistance is very feeble, it being always less than a tenth of an ohm when the pile is in a good state, and the electromotive force being that of the Daniell element--about 1 08 volts.

Sometimes the zinc is covered with a sheet of parchment which more thoroughly prevents a mixture of the liquids and a deposit of copper on the zinc. But such a precaution is not indispensable, if care be taken to keep up the pile by taking out some of the solution of sulphate of zinc every day, and adding sulphate of copper in crystals. If the pile is to remain idle for some time, it is better to put it on a short circuit in order to use up all the sulphate of copper, the disappearance of which will be ascertained by the loss of blue color in the liquid. In current service, on the contrary, a disappearance of the blue color will indicate an insufficiency of the sulphate, and will be followed by a considerable reduction in the effects produced by the pile.

The great power of this pile, and its constancy, when it is properly kept up, constitute features that are indispensable for the proper working of the siphon recorder--the application for which it was more especially designed.

This apparatus has been also employed under some circumstances for producing an electric light and charging accumulators; but such applications are without economic interest, seeing the enormous consumption of sulphate of copper during the operation of the pile. The use of the apparatus is only truly effective in cases where it is necessary to have, before everything else, an energetic and exceedingly constant current.--_La Nature_.

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SIEMENS' TELEMETER

The accompanying cut illustrates a telemeter which was exhibited at the Paris Exhibition of Electricity, and which is particularly interesting from the fact that it is the first apparatus of this kind. It will be remembered that the object of a telemeter is to make known at any moment whatever the distance of a movable object, and that, too, by a direct reading and without any calculation. In Mr. Siemens' apparatus the problem is solved in the following manner: