October 17, 1S84.] 



SCIENCE, 



389 



force generated in these plates, tending to buckling, 

 is something enormous. 



I do not think any ordinary separator of material 

 which he speaks of would be sufficient to prevent the 

 buckling of a Yolckmar accumulator; for the force 

 generated in these plates, tending to buckle them, is 

 something enormous, and no ordinary separator would 

 be able to resist this. If such resistance were offered 

 to them, I think they would break. The reason why 

 he has succeeded in getting rid of this buckling is 

 because he has reverted to what is evidently the most 

 scientific, and which will ultimately be found to be 

 the most probable, form, that of the old voltaic bat- 

 tery. The objection to the Faure cell was the want 

 of perfect symmetry in the plates, tending to make 

 them buckle, and want of homogeneity in the sur- 

 face, which tended to introduce local action. And 

 that is the one great defect which has been pointed 

 out some time ago, which I think most people recog- 

 nize now in all these Faure cells and Yolckmar bat- 

 teries. 



I wish Mr. Preece would give us some further in- 

 formation about the length of life of these cells; be- 

 cause although he has them in his charming house, 

 and although they last only four months, does not 

 everybody who will call want to obtain some more 

 definite information? and I think there must be some 

 gentleman here who can give us more information 

 about the life of these batteries. As a matter of fact, 

 the larger form of Plante battery, the improved type 

 of batteries, which I believe were tried generally with 

 nitric acid in order to render them more powerful, 

 have been generally used with lead, but only within 

 the last year or two, and therefore their absolute life 

 is not determined; but I believe it is perfectly con- 

 ceded that these voltaic batteries as they have been 

 prepared with lead, and as Mr. Preece has them in 

 his own establishment in his own private house, are 

 the longest-lived batteries, — far longer lived than 

 any artificial batteries such as the Faure cell and the 

 Yolckmar. 



Mr. F. C. Yax Dyck. — I do hope the people will 

 not be discouraged in working in the line of other 

 batteries besides the old one. I think there are cases 

 in which the battery is sure to have a long life, and 

 sure to keep itself charged without loss for a great 

 length of time. 



There are many uses for such a battery as that; 

 and my own work satisfies me that the zinc alkaline 

 and copper battery will fill a considerable want; 

 for instance, running the magnetic apparatus in ob- 

 servatories, and work of that kind. I have made a 

 small battery of that kind, using a spiral of copper 

 above, and amalgamated zinc below, so as to avoid 

 the falling-down of the deposit of zinc upon the cop- 

 per, thereby amalgamating the copper, and render- 

 ing it far less efficient. Although the electromotive 

 force is only ninety-seven and ninety-eight hundredths 

 of a volt, still we found by actual trial that charging 

 the battery and letting it stand, then letting it run 

 down and taking the readings at the time, and then 

 letting it stand for two or three months — we found 

 there was not enough difference in the readings to 



show the slightest loss ; the battery had retained its 

 charge, so far as we could find out by the means at 

 our command, perfectly for two months; which I 

 think is a good showing. Long ago I found, in using 

 a battery, that I had to be very particular about the 

 electromotive force to be used in charging it. I have 

 not finished my experiments so as to state precisely 

 the electromotive force, but it is somewhere between 

 a Daniell and a Grove. If you charge a cell of that 

 kind with a Grove cell, you will find that the copper 

 strip will be altogether dissolved by alkaline solution, 

 forming the cuprate of soda or potash, according to 

 the alkaline used. Then that breaks up in the form 

 of oxide of copper. But, if you are particular about 

 not running beyond the Daniell, there is no such dif- 

 ficulty experienced. 



I want to say a word on the carbon question. I 

 am interested to know whether anybody has succeeded 

 in producing oxygen on carbon to any considerable 

 extent without disintegrating it. I have had great 

 difficulty, in my experiments with the secondary bat- 

 tery, in getting oxygen on my carbon plate, and 

 depositing the oxide of lead. I have found, if I suc- 

 ceed in bringing forward the oxygen in the slightest 

 degree, it leads to the disintegration of the carbon 

 by means of the oxygen. Hydrogen does not do it 

 at all. Now, if we place a carbon disk with a plati- 

 num disk in an ordinary Yolckmar battery, we will 

 soon discover how long that carbon will last. The 

 oxygen seems to have the power of forming an accu- 

 mulation in the pores, and crowding out the carbon, 

 more than the hydrogen does. I dislike to have any 

 thing to do with the lead-battery mentioned. I think 

 that this matter of the copper-battery is worthy of 

 passing mention, because I can see those cases arise 

 in which we should like to have a battery that we 

 could charge, and know we could depend upon, and 

 that would not lose its charge even after two months. 

 I am positive that anybody who tried it would be 

 pleased with the properties of the copper-battery 

 made in the usual way, with amalgamated zinc alkali, 

 either soda or potash. Preference should be given 

 to soda on account of its being so much cheaper. 

 The method should be to use the Plante battery with 

 chlorate of sodium in it. I think the tendency of 

 the copper to dissolve, and to break up into cuprate 

 forms, is not any greater when the soda is used. 



Mr. Koyle. — I just wish to inquire of Professor 

 Yan Dyck how his carbon is made: it makes consid- 

 erable difference. I should like to know the manner 

 in which the carbon plates are formed. If they 

 are formed by the ordinary method for use in the 

 primary batteries, the carbon being made out of coal- 

 tar carbonized, they are very brittle, and disinte- 

 grate in the battery; but if formed in the manner 

 I speak of, from coal-tar, pure and simple, so that 

 they seem to form a very much more homogeneous 

 mass, there is not only a striking, but a permanent 

 difference of the plates. 



Professor Yan Dyck. — I will state that I use the 

 commercial carbon simply. 



Mr. Koyle. — Another word. I think that there 

 is a great deal of difference between the secondary 



