154 THE MICROSCOPE. Oct. 



QUESTIONS ANSWERED. 



HoTB.— Dr. S. G. Shanks, of Albany, N. V., kindly consents to recen^e all sorts of ques- 

 tions relating to micros-c^pv , whethe' asked l-y t>rofessionals or nni.il.ws. Persons of aU 

 f ades ofexf>erience,froiii 'the l>,i;^i>tuey i,/>wa>d, are wlcuvte t-< the bcf.fits ./tins dtpa^' 

 Dtent. The questions are nuiiil;' • d /or /unit e > e/erence. 



202. Who are the best authors cm histology and urinary analysis 

 — Hardy, 



Tyson, Kxanniiation of Urine, cost SI 50. 



Hofmann and Uitzmann, Analysis of Urine, cost $2.00. 



Klein, Elements of Histology, cost $1.75 



Stirling, Practical Histoloiry, cost S3.00. 



All are good works on their subjects. 



203. Is the " Wenham^' stand described in Hogy's ''The Micro- 

 sccype.^^ now on sale f Is it not a very good one f — R. Eich. 



The stand figured in Hogg, was intended to illustrate a 

 binocular stand furnished with a Wenham i)rism; the Wenhain 

 prism is the one commonly used in binocular stands and is a 

 very good one. 



204. Who noiv sells the Bullock stands ?—R. Rich. 

 E. B. Meyrowitz, 104 E. 23rd St., New York. 



205. What is a " Spot Lens " f—S. 



Carpenter says a spot lens is a condenser with a i)ermanent 

 axial stop fixed in it to cut off the central rays for the purpose 

 ot obtaining a dark ground upon which the illuminated object 

 lies. Obviously it is not a desirable accessory. It is a con- 

 denser, but having a fixed stop it can only be used for this mode 

 of illumination. 



PRACTICAL SUGGESTIONS 



By L. A. WILLSON, 



CI.KVKLAND, OHIO. 



A Double Nose-Piece. — The i)art of a double nose-piece 

 sup}>()rting tlie unused objective should stand perpendicularly 

 out from the tube of the microscope. If allowed to be on one 

 side it will prevent the proper revolution of the objectives and 

 will subject them to gi'eat danger. No accessory can afford more 

 comfort, save more time or wear and tear than a nose-piece. 



