SOIENOE— ADVERTISEMENTS 



HiLGER 



Quartz Spectrograph 



IN OUR STOCK FOR IMMEDIATE SHIPMENT 



No. 46945 Hilger Quartz Spectrograph, size (a) 



46945. SPECTROGRAPH, QUARTZ, HILGER SIZE (a), for work in the ultra- 

 violet, with an objective of 8-inch focus giving a spectrum from 2001111 to Soofiij, 

 of about 65 mm. long. Size of plate 4^4^ ^3% inches. The slit supplied with this 

 instrument is Hilger No. i, i. e. with fine screw adjustment, with divided drumhead, 

 comparison prism, wedge for reducing the aperture, screws for correcting want of 

 parallelism of the jaws, should this become necessary at any time, and protective cap. 

 The dispersing system consists of one Cornu prism. With wave-length scale photo- 

 graphed on glass to be laid directly on the spectrograms to read off wave-lengths and 

 of sufficient accuracy to determine the identity of most lines. Wave-length scale can 

 not be supplied separately as it is adjusted to each individual instrument. 



Price, from duty paid stock . . ■ $315.16 



Price subject to change ivithout notice 



ARTHUR H. THOMAS COMPANY 



WHOLESALE. RETAIL AND EXPORT MERCHANTS 



LABORATORY APPARATUS AND REAGENTS 



WEST WASHINGTON SQUARE 



PHILADELPHIA, U. S. A. 



