1894 THE MICROSCOPE. 183 



der, if at all lumpy. Take a clean glass slip, place a very small 

 drop of liquid balsam on the center. Let some of the fine 

 starch fall into the balsam from the point of a knife. Set the 

 slide away for 24 or 36 hours, 'covered from the dust. When 

 the balsam is shghtly hardened, shake off the surplus starch, 

 drop a little frf^sh balsam on the hardened mass, put on a cover- 

 glass. Place a weight or clip on the cover and set aside to 

 harden completely. The first or hardened drop of balsam will 

 soften slightly and spread uniformly carrying with it the starch. 

 Two specimens of starch may be thus mounted under one 

 3over for comparison and be kept separate. 



212. / have just come into the possession of a microscope, hut 

 know very little about its use. How may I best become an expert 

 with it f— REV. J.J. Z. 



Clark's Practical Methods in Microscopy, published by Heath 

 & Co., Boston, will teach you how to use the microscope and 

 how to prepare objects for microscopic examination. 



213. / have a full line of Zeiss objectives and a Photomicro graphic 

 outfit. What is the literature of the subject and what dealers in sup- 

 plies do you recommend ? 



The A. M. M. J., for 1886 contains a very full continued arti- 

 cle by R. Hitchcock. The volumes for 1890-91 and '93, also 

 contaiu valuable articles on Photomicrography. Clark's Prac- 

 tical Methods in Microscopy, contains a practical article on the 

 subject. Supplies may be had from any good dealer in photo- 

 graphic supplies. See our advertising columns. 



PRACTICAL SUGGESTIONS. 



ByL. A. WIIvLSON, 



CLEVELAND, OHIO. 



How to Mount Objects in Motion for Examination by- 

 Polarized Light.— Use a rubber cell 1-16 of an inch deep and 

 3-4 cover. For a medium, use Canada balsam thinned with 

 not quite an equal bulk of spirits of turpeotine. Stir well to- 

 gether and when dissolved filter through cotton. Cement the 

 cells to the slide with something not acted on by turpentine — 

 for example, shellac, or sealing wax in alcohol. The objects 



