NO. 12 



SPECTROBIOLOGY BRACKETT AND McALISTER 



under sterile conditions. Furthermore, provision is made to traverse 

 the spectrum with a thermocouple. This is supported by a worm- 

 driven dovetail slide. Last, a second slit may be supported in place 

 of the thermocouple and the instrument used strictly as a mono- 

 chromator. Provision has been made for automatically recording the 

 galvanometer deflections when the spectrum is traversed by the thermo- 



FiG. I. — Diagram of optical arrangement. 



couple. The instrument is provided with, scales and is of such rigid 

 construction as to make possible a high reproducibility of setting. 



Plate I shows the. spectrograph with the prisms exposed. A number 

 of unique features will be noted ; the extra long slit is supported by 

 parallel rods which extend so as to carry the source and the condenser 

 lenses when used. This permits the swinging of the collimator without 

 realignment of the preliminary system. As will be noted, the instru- 

 ment extends from one room to another. Provision is made for 



