1866.] MISCELLANEOUS. 79 



should be placed first in solution B 2 to obtain the best results. 

 In cases where the use of the B. fluids would be objectionable, on 

 account of their highly poisonous nature, a fourth dilution of 

 solution A 1, corresponding in strength with B 1, but without 

 the arseniate of potassa, may be substituted, and in many cases 

 will do nearly as well, if the weather be not very hot, but the 

 specimens in this case should be carefully watched and transferred 

 to the stronger solutions as soon as possible, so as to avoid incipient 

 decomposition while in the first fluids. — SiUimans Journal. 

 New Haven, Feb. 12, 1866. 



Illumination under the Microscope. — At the late soiree 

 at University College, two forms of Mr. Smith's (of the United 

 States) illumination for opaque objects under high microscopic- 

 powers were exhibited. One was constructed by Messrs. Smith 

 and Beck, of Cornhill, and the other by Messrs. Powell and 

 Lealand. The first form closely resembles the American contri- 

 vance — so closely, indeed, that it is difficult to know in what the 

 difference between the two consists. A bass box intervenes 

 between the end of the microscope tube and the objective. This 

 is pierced at the side by an aperture opposite which a table lamp 

 is placed ; within the box is a small silvered mirror, which receives 

 the light from the lamp, and throws it down through the objective 

 upon the object. This contrivance, thought it works admirably 

 with such a power as the one-fifth inch, is objectionable, from the 

 fact that it cuts off half the pencil of rays proceeding to the eye 

 of the observer. The second form — that exhibited by Messrs. 

 Powell and Lealand — is superior to that of Smith and Beck, and 

 differs from the American plan in having a reflector of plain glass. 

 The result of this alteration of the original plan is that whilst, 

 sufficient light is thrown down to illuminate the object, the rays 

 proceeding from the latter are not partially cut off. This modifi- 

 cation applied to the one-twelfth inch gave splendid results, and 

 the makers allege that it may be used with one-twenty-fifth or 

 one-fiftieth inch glasses with equal advantage. — fieader, Pec. 23. 



The Birds of North America. — D. G. Elliot of New 

 York (27, AY. 23d st.) proposes to publish a work to contain all 

 the new and unfigured birds of America, to be issued in Parts, 

 19 x 24 inches in size, containing each five plates colored by 



