146 THE AMERICAN MONTHLY [May, 



(33) Titles. — I should like to see a bibliography of the original 

 articles that appear in microscopical technique and in the various 

 sciences in which the microscope is used. A complete list of 

 books, papers, etc., etc., is good. I have a card catalogue of all 

 you published already. For indexing the periodicals, etc., the 

 size of card that you suggest is good, but for indexing articles, 

 some prefer other sizes. A printed label is, of course, much bet- 

 ter than a written one. V. A. Moore. 



Washington, March 22. 



(34) Titles. — The scheme is admirable. I wish you would 

 include the price and number of illustrations. These facts are of 

 value to one selecting books to purchase. A. P. Weaver. 



Jackson, March 24. 



(35) Titles, — I was struck vvitli this plan. It must be very- 

 useful. I would suggest, however, (i) larger type, (3) names of 

 authors in bolder type, (3) additional space between the items. 

 The small type may be trying to the eyes of middle-aged people. 



J. P. Thompson. 

 Portland, March 22. 



(36) Titles. — I have used such a scheme as you propose for 

 several years and your lists would have saved me a good deal of 

 trouble. I find a few new items in your February list. I will 

 help on this work as soon as I get settled. J. M. Steedman. 



Auburn, Ala., March 30. 



(37) Titles. — The scheme I think a good one. I should ad- 

 vise that each title be printed twice, so that two cards can be 

 made — one for authors and one for subjects. I have used such an 

 one for a long time ; every article worth keeping track of is en- 

 tered. Leave space between the titles so as to make it easier to 

 cut and paste them. H. L. Osborn. 



St. Paul, Minn., March 20. 



(38) Titles. — I do not see the utility of a mere list of books, 

 as but few of us have so extensive a library as to render it neces- 

 sary to catalogue them, but a list of all microscopical books, giv- 

 ing a short review of the contents and the prices, would be a 

 consideration and assist intending purchasers. S. G. Shanks. 



Albany, N. Y., March 37. 



MICROSCOPICAL APPARATUS. 



Micrometer Calipers. — This instrument is convenient for 

 measuring the thickness of cover-glasses. That it was not 

 mentioned by Prof. S. H. Gage in his recent volume was purely an 

 oversight and not a lack of appreciation nor of knowledge. Prof. 

 Gage writes us that when he tried the calipers in comparison with 

 cover-glass measurers the results obtained on the same glasses 



