Improvements in the Microscope. 57 



{g,) Skeletons. The skin should be taken off, the flesh, the vis- 

 cera and the brains removed and all the parts covered with arsenical 

 soap. The feet should be bound close to the body and the skeleton 

 hung up to dry. The same simple course is applicable to all verte- 

 bral animals. Animals prepared in spirits of wine should be packed 

 together as mentioned above. 



***** 



The recipe for making arsenical soap is as follows. 

 White arsenic, > i lu 1 



_, , ^' -^ . -7 I As much warm water as the 



Camphor, 43^ 



UnslackedLime, 2" f mixture requires. 



Potash, 6 " J 



N. B. The arsenic should be rubbed with water until it is finely 

 pulverized. The soap should be melted, and the arsenic gradually 

 mingled with the other substances and the whole stirred over a slow 

 fire until it is thoroughly mixed. The vessel which contains it must 

 then be removed to some distance, and the preparation made in the 

 open air. Arsenical soap may also be manufactured out of arsenic and 

 common soap, provided the other ingredients are not to be procured. 



Art. VIII. — On improvements in the Microscope ; by Edward 

 Thomas, late assistant engineer on the Cayuga and Seneca Canal. 



The Achromatic Microscope is superior to all other kinds where 

 great power is necessary. It was " first constructed [in Europe] at 

 the suggestion and expense of Dr. Goring, by Mr. W. Tully, in the 

 summer of 1824."* This kind has more recently been constructed 

 in this country by my friend Alden Allen, of Boston, (who has exe- 

 cuted them with great skill,) and by myself. I have constructed 

 them of the double, treble, quadruple, quintuple, and sextuple forms, 

 the two last of which are the best, when the achromatic lens is de- 

 signed for the object-glass of a compound microscope. 



A quintuple object-glass of mine, which is represented in section 

 by Fig. 1, consists of two concave flint lenses and three convex lenses 

 of plate glass. The lenses of flint glass are represented in the fig- 

 ure by the dark, and the plate lenses by the white spaces, O being 



* See "Library of Useful Knowledge, " No. 21, page 46. 



Vol. XIX.— No. 1. 8 



