374 THE AMERICAN MONTHLY [Dec 



Bartholomew has published (Trans. Kans. Acad. Sci. 

 16:168) a valuable list of the Kansas Uredineas. He has 

 broug-ht tog-ether a comprehensive list of the diseases as 

 they occur in that state. Kansas has had several valuable 

 collectors, Hitchcock, Kellerman, Carleton, Swing-le and 

 Norton, all of w^hom have added largely to the known 

 species of the Uredineae of that state, Bartholomew cites 

 some of the literature of the species and g-ives a complete 

 list of the host plants, making this, indeed a very valua- 

 ble contribution. 



MCEOSCOPICAL APPARATUS. 



New I -12 inch Immersion Objective. — Messrs. R. and 

 J. Beck have a new 1-12 inch immersion objective with a 

 numerical aperture of 1.4 and an aplanatic cone of 1.35 N. 

 A. It is perfectly achromatic, and the makers modestly 

 and rightly claim no more than this. It is exceptionally 

 free from color,the definition is excellent,and theincreased 

 quantity of light passed is most noticeable. It bears com- 

 paratively high eye-piecing well. The working distance is 

 of coarse rather less than in objectives of lower aperture. 

 The price brings it within the reach of all workers requir- 

 ing an objective of this description, being $40 or $48 with 

 correction collar. 



New Immersion Condenser. — Messrs. Beck have out a 

 new immersion condenser, with a numerical aperture of 

 1.36 to 1.4, and an aplanatic cone of 1.3 N. A. The combi- 

 nation consists of four systems of lenses, the front of 

 which is a hemisphere with three combinations behind, and 

 constructed on the principle of anoil-immersionobjective. 

 Testing this condenser in connection with the objective 1.4 

 N. A. above described is one much pleased with its per- 

 formance. The working distance is 0.6 inches. By an in- 

 genious arrangement the optical part of the condenser can 

 be reversed in the mDunt so that it may be used with mi- 

 croscopes fitted with under-stage fitments instead of the 

 usual focussing substage. The top lens is also removable. 

 The price of the optical part is $13 ; of the mount, with iris 



