198 



ANNUAL OF SCIENTIFIC DISCOVERY. 



JTia.2 



reflection, they are thrown on the ocular or anterior cathetus, also shaped 

 like a lens. The distance between the objective glass and the eye is conse- 

 quently but the thickness of a prism (hardly two inches), the real length of 

 the apparatus becomes vertical, is hidden inside the handle, which affords the 

 observer a means to hold it in a steady position. The arrows indicate the 

 direction in which the rays of light are reflected. The exterior shape, fig. 2, 

 is very handy, not liable to get out of order, and the whole is quite portable, 

 and the instrument very powerful. A is the eyeglass. B thumb screw for 

 regulating the focus. The greatest difficulty the inventor had to contend 

 against was to obtain perfect achromatism ; in this, we are told, he has 

 fortunately succeeded perfectly; his instruments are as free from colored 

 spectra and aberration as the most perfect spy-glasses constructed in the 

 ordinary manner. A small micrometer is also adapted for the purpose of 

 computing distances. 



CUKIOUS USE OF THE MICKOSCOPE. 



Recently, on one of the Prussian railroads, a barrel which should have con- 

 tained silver coin, was found, on arrival at its destination, to have been 

 emptied of its precious contents, and re filled with sand. On Professor Ehren- 

 berg, of Berlin, being consulted on the subject, he sent for samples of sand 

 from all the stations along the different lines of railway that the specie had 

 passed, and by means of his microscope, identified the station from which the 



