no 



THE AMERICAN MONTHLY 



[June, 



for histological work, with an angle 

 of 95° — made for some investigations 

 preliminary to a lecture on the forma- 

 tion of the tissues with special refer- 

 ence to the nervous system, and mar- 



The " Acme " No 3, Improved. 



Messrs. J. W. Queen & Co. have 

 recently introduced a new stand which 

 they designate as the " Acme No. 3. 

 New Model, " which has many claims 

 upon microscopists who wish to pur- 

 chase stands worth from $55.00 to 

 $75.00. Its merits can be fully under- 

 stood by an ex-amination of the illus- 

 tration (tig. 20). The following de- 

 scription is condensed from the cir- 

 cular of the manufacturers : 



The entire stand is of brass, highly 

 finished. The draw-tube is turned out 

 larger inside below the top, so that 

 the long eye-piece does not rub off the 

 black finish, hence there is no bright 

 surface to cause reflection with the 

 shorter eye-pieces. The eye-pieces 

 are designated by their equivalent 

 focal length. 



Fig. 20. —The "Acme" No. 3, Improved. 



vellous is the help which the superb 

 lens has given to me in my histologi- 

 cal studies. 



Bangor, Me., April 24th, 1883. 



The rack-and-pinion adjustment has 

 a long range. The fine adjustment is 

 a very delicate and truly-working one, 

 suitable for the highest powers. The 



