ANTIMONY SOLUTIONS.] UNDULATORY FORCES. ELECTRO-METALLURGY. 



dissolves the anode freely ; yields plenty of bright regu- 

 line metal if the battery power be sufficiently weak ; and 

 its depositing power does not deteriorate by exposure to 

 light or the atmosphere, but it appears to be gradually 

 exhausted by working ; it is also decomposed more or 

 less rapidly by zinc, tin, lead, iron, brass, copper, and 

 German silver, each of which coat themselves in it with 

 antimony by simple immersion ; and articles immersed 

 in it require to be washed with hydrochloric acid before 

 washing them with water, otherwise the latter decom- 

 poses the adhering liquid, and covers, them with a white 

 insoluble powder. 



98. The mixed chlorides of antimony and ammonia 

 form a very good depositing liquid. It may be pro- 

 duced either by the battery process, by mixing one mea- 

 sure of a saturated solution of sal-ammoniac with one 

 measure of hydrochloric acid, and working antimony 

 into it by means of a battery and a large antimony 

 anode ; or by simply mixing together equal measures of 

 a saturated solution of sal-ammoniac and commercial 

 chloride of antimony. This solution conducts easily, 

 yields its metal freely and of good quality, and does not 

 act so strongly upon base metals as chloride of antimony 

 alone ; but in other respects it is similar to the chloride. 

 The mixed chlorides of antimony and manganese, or of 

 antimony and bismuth, yield a reguline deposit easily, 

 but do not appear to possess any special advantages. 



' '. The potassio-tartrate of antimony is a salt not 

 very soluble in water ; its aqueous solution is a very 

 bail conductor of electricity, and is not to be compared 

 to the chloride for depositing purposes. We have never 

 been able, either with strong or weak batteries, to de- 

 posit from it anything better than a small quantity of 

 antimony in the state of a perfectly black powder : on 

 the other hand, its solution in hydrochloric acid (which 

 dissolves it very freely), or hydrochloric acid and water, 

 is by far the best that we have tried for depositing anti- 

 mony : it is an excellent conductor of electricity ; it is 

 not impaired by long working or exposure to light or 

 the atmosphere (we have deposited antimony from it 

 constantly during many months) ; it will bear a great 

 amount of battery power without the deposit passing 

 into the state of a loose powder ; it deposits reguliii': 

 metal very rapidly and in groat thickness. We have ob- 

 tained such deposits from it upwards of two inches in 

 thickness ; articles immersed in it wash clean in water 

 alone, without the previous use of hydrochloric acid. It 

 may be made by mixing together about two pounds of 

 "water, four pounds of hydrochloric acid, and sight 

 ]>ouuds of potassio-tartrate of antimony ; a greater pro- 

 portion of water may be used if desin-d. 



100. Both the black and red sulphides of antimony 

 dissolve in cold hydro-sulphate of ammonia, and the 

 resulting solutions conduct very freely with an antimony 

 anode and one cell of Smee's battery, but yield no de- 

 posit of metal even with a battery of twenty-five cells' 

 intensity. Aqueous solutions either of caustic potash, 

 tartrate of potash, or oxalate of potash, scarcely conduct 

 at all with an anode of antimony, and a battery con- 

 sisting of one or two cells. Cyanide of antimony, dis- 

 solved in a solution of cyanide of potassium, has been 

 proposed as a depositing liquid ; but wo have found a 

 solution of cyanide of potassium to be a very bad con- 

 ductor with an anode of antimony. 



101. Antimony is one of the easiest metals to deposit 

 in tho rcgnlino state; its appearance when deposited 

 from the chlorido solutions, and from the solution of 



>tassio-tartratc in hydrochloric acid, is very beau- 

 tiful ; and when deposited slowly, it has much of 

 the lustre of highly-polished steel. Some of its pro- 

 ]xjrties when thus deposited are very peculiar and in- 

 teresting, especially with regard to heat. If, during 

 any part of the time the deposit is progressing, the 

 deposited antimrny be taken out and struck gently, or 

 nibbed with any hard substance, such as metal or glass, 

 an explosion will occur, accompanied with a small cloud 

 of whiti; vapour sometimes with a flash of light, and 

 nearly always with considerable heat, sufficient to burn 

 the fingers, melt gutta-perc.ha, burn paper and even 



scorch deal wood to a brown colour, especially if tho 

 deposit be thick. This is invariably accompanied by 

 fracture of the deposited metal ; sometimes, when the pro- 

 cess of deposition has been interrupted, and tho de- 

 posited metal is not homogeneous, the fracture extends 

 through the metal to upwards of one-eighth of an inch 

 in depth. This phenomenon has been observed many 

 times, both before and since its first publication ; in 

 several instances the explosion was produced even in the 

 liquid, by striking the deposit against tho glass vessel 

 which contained it ; and in one instance it occurred after 

 the metal had been well washed with dilute hydrochloric 

 acid, dried, and had remained out of the liquid several 

 hours. 



On one occasion, a deposit had been well washed, 

 dried, and out of the solution many hours ; and a friend, 

 in course of conversation, was unconsciously breaking 

 small portions off it with his fingers, when it became 

 suddenly heated, and exploded, causing a slight noiso 

 like the lighting of a congrevo match, and burning his 

 fingers. In other cases, a deposit has been progressing, 

 and has been removed an instant for examination, and 

 the battery liquid strengthened by the addition of acid : 

 upon examining the deposit a few hours afterwards, it 

 has been found cracked in various directions, as if an 

 explosion had occurred in the interval, although tho 

 apparatus had been undisturbed. A French writer has 

 suggested that this deposit is a compound of antimony 

 and hydrogen ; and from the fact that the explosions 

 occurred when the metal was depositing rather rapidly, 

 we are inclined to think his explanation correct ; the 

 extra power, as we have seen in other cases (94, 95), 

 causing hydrogen deposit, which, in its nascent state, 

 instead of being evolved, might combine with the metal 

 and form an explosive compound. Another suggestion 

 we would make is, that the metal may be deposited in a 

 peculiar condition of unequal mechanical tension, similar 

 to that of unannoaled glass, and that, by breaking, tho 

 closer aggregation of the particles may develop light 

 and heat. 



102. Another peculiarity in depositing antimony from 

 tho potassio-tartrato solution is, that if the solution be 

 a very dense one, and the process long continued 

 without disturbance of the liquid, tho deposit occurring 

 upon the cathode will slowly spread out in the form of 

 a thin sheet upon the surface of the liquid, until it 

 touches the anode ; whilst the deposit beneath progresses 

 very slowly. We have a button of antimony formed 

 in this way upon a vertical copper wire, one and five- 

 eighths inches in diameter, tho deposit beneath tho sur- 

 face of tho liquid having been only half an inch thick ; it 

 occupied about eighteen days, with a small cell of Smee's 

 battery, in forming. Deposits of antimony formed in 

 the above solution do not spread over blackleaded sur- 

 faces of gutta-percha, nor do they adhere with any great 

 degree of firmness to copper, brass, or iron. 



103. Bismuth Salts. The most usual compounds of 

 bismuth are the chlorido, mononitrate (pearl white), and 

 ternitrate. The chloride is formed by digesting bis- 

 muth filings a long time in a warm place with hydro- 

 chloric acid. The mononitrate is formed by dissolving 

 bismuth to saturation in warm dilute nitric acid, and 

 then adding a large quantity, say fifty or a hundred 

 times its volume, of water ; the precipitate produced, 

 when well washed with water, is the substance required. 

 Tho tornitrate is formed by dissolving the metal in hot 

 nitric acid, evaporating the solution, and leaving it in a 

 cold place to crystallise. Bismuth may easily bo de- 

 posited from a solution formed by dissolving either 

 mononitrate or ternitrato of bismuth in dilute nitric acid, 

 but it requires an exceedingly feeble current to deposit 

 it in a reguline state ; its appearance when so deposited 

 is very beautiful white with a faint pinkish tint, and 

 with a fine silky lustre ; it does not spread over black- 

 Ir.-iiVd surfaces of gutta-percha in this liquid. A bis- 

 muth anode does not dissolve readily in a hot solution 

 of cyanide of potassium. 



104. Zinc Salts. There are a variety of salts of this 

 metal in ordinary use, the most common of which arc 



