46 THE AMEKICAN MONTHLY [February, 



his large Powell and Lealand stand. The objective was a horn. imm. 

 I-", the companion lens to Mr. Carter's, and the illumination was by 

 means of a Wenham Reflex. The test in balsam being much more 

 difiicult than that in Smith's medium, the details of form and mark- 

 ings were not seen with the same clearness, but the result w^as highly 

 satisfactory and was probably as fine as could be accomplished with 

 that particular diatom. Dr. G. S. Allan exhibited a Podura scale 

 with his Apochromatic Jg" and satisfied the Society that for central 

 light at least this glass has, as yet, no equal. A comparison w^as then 

 made between this lens and a fine Water imm. y^" upon the same 

 scale, showing the superiority of the former in the matter of achrom- 

 atism. Dr. Allan had also a dry ^" of Powell and Lealand's make. 

 One characteristic of this glass is a long working distance. It turned 

 out to be a very valuable objective, as was proven by trying it upon 

 some histolosrical slides. 



Microscopical Society, Washington. D. C. 



82d Meetings Tuesday^ Oct. 2J, 1888. — Dr. Taylor exhibited a 

 large number of photographs of microscopical objects, the most of them 

 by Dr. G. W. Rafter, of Rochester, N. Y. He also spoke of his ex- 

 amination of spices with reference to adulteration. Beautifully drawn 

 and colored sections were shown. As in pepper the cellular structure 

 varies, many sections should be made. Sulphuric acid will bring out 

 the oil cells. He also made sections of cloves. The principal adul- 

 terants of pepper are ground cocoa, nut-shells, and ground olive stones. 

 White pepper is more adulterated than black. 



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83d Meeting., Nov. /j, 1888. — Mr. Chapman reported experiments 

 with crystallized carbolic acid. Having poured some water on it, then 

 poured off' the water and added 95 "0 alcohol, then poured this off" and 

 added water to the remainder of the acid, the two aqueous solutions 

 had become discolored while the alcoholic solution remained clear. 

 He found that insects clear up well in the alcoholic solution. Dr. 

 Taylor said that his experience had been that alcohol and carbolic acid 

 contracted the limbs of insects, but the addition of chloroform would 

 relax them. 



Dr. Taylor read a paper on a freezing microtome invented b\- him. 

 It will be printed in full in the microscopical journals. 



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Leavenworth. — W. D. Bid well. Secy. 



Jan. 7, i88g. — A regular meeting was held at Dr. Bidwell's office. 

 The subject was the optical principles involved in determining angular 

 aperture, and the value of a large angular aperture. Prof. Lighton ex- 

 hibited a diagram showing the points under discussion very lucidly. 

 He also spoke of some experiments he is making to obtain a material 

 which will supplant the Nickels prism, the idea occurring to him as a 

 slide of selenite mounted in styrax lay upon his hand in the sunlight. 



Dr. Bidwell described and showed the advantages of his new cabinet 

 for slides. Drs. Van Eman and Carpenter discussed some of the dif- 

 ficulties of section cuttinsf. 



