1885.] 



MICROSCOPICAL JOURNAL. 



97 



into general use it must be reasonably 

 convenient, and it must not be far re- 

 moved from a kerosene lamp in this 

 respect. It is true there are decided 

 advantages in the excellence, purity 

 and brilliancy of the electric light, 

 which make it very desirable. Never- 

 theless, these advantages are not so 

 great as will induce observers to put 

 up with the nuisance of ordinary bat- 

 teries. 



Among those who have been quick 

 to recognize the value of the electric 

 light in microscopy is Mr. Edward 

 Bausch, who, in the springof 1882, be- 

 came interested in the subject, and in 

 that year made use of an electric at- 

 tachment at a public exhibition of 

 the Rochester Academy of Sciences 

 constructed substantially like that now 

 made b}- Messrs Bausch & Lomb. 

 Later in the same year it was shown 

 at the meeting of the American So- 

 ciety of Microscopists, at Elmira. 

 Mr. Bausch believed that his appli- 

 cation of the electric light to the mi- 

 croscope was new. and he therefore 

 applied for letters-patent, which were 

 granted May 32d, 1883. To Mr. 

 Bausch belongs the credit of having 

 quickly appreciated and practically 

 applied a source of light which is sure 

 to grow in popularity, when suitable 

 batteries are devised. 



A number of different kinds of bat- 

 teries have been made already, and 

 as we may expect some of them to be 

 offered for microscopical use, it may 

 be well at this time to mention some 

 facts about batteries in general. 



In the first place it does not seem 

 to us advisable to recommend any 

 battery that will not run a one candle 

 power lamp at its full brightness at 

 least three hours without intermission. 

 This can easily be done with a large 

 battery — one which exposes consider- 

 able surface of zinc and carbon, and 

 holds considerable fluid. But a large 

 battery of even one or two cells is 

 only desirable when one can store it 

 out of the way, and use it always in 

 one place. 



The problem is, how to make a 



durable small battery. This has not 

 yet been accomplished, so far as we 

 have heard ; but there are several 

 promising devices under way, which 

 may lead to a solution of the problem. 



Among the large batteries we were 

 well pleased with a couple of cells 

 which were recently at work in Mr. 

 G. S. Woolman's establishment at 

 New York. These gave a very good 

 light, which would probably last 

 many hours. 



Passing to the other extreme, there 

 are offered very small batteries, scarce- 

 ly larger than an ordinary collar-box, 

 which are said to give a good light. 

 Such batteries are practically useless 

 for microscopical work. T'he pro- 

 duction of electricity involves the con- 

 sumption of a certain amount of zinc 

 and battery fluid, and a very small 

 battery cannot furnish enough of 

 either. The amount of electricity 

 produced in a given time depends 

 upon the rapidity of the chemical ac- 

 tion in the battery, and this is largely 

 dependent upon the extent of surface 

 exposed. It seems likely that a satis- 

 factory battery will be made which 

 will go in a box of a cubic foot ca- 

 pacity, this space allowing for the re- 

 moval of the zincs from the fluid 

 when not in use. One can scarcely 

 expect anything smaller than this 

 that will be convenient for use. un- 

 less new combinations of fluids are 

 employed, of which we may hear 

 more anon. 



We would advise all purchasers 

 of batteries to be careful about choos- 

 ing their lamps. There is a great 

 difference in lamps of different makers, 

 some requiring far more battery power 

 to run them than others. The Edi- 

 son lamps are good. 



NOTES. 



— Mr. R. D. Nevins, of Olympia, 

 Washington Territory, has sent us some 

 beautiful specimens of a marine plant 

 covered with diatoms. One specimen is 

 thickly spread with Arachnoidiscus, and 

 the other has the same diatom and many 

 others, including Isthtnia and Tricera- 



