CENTRAL SCIENTIFIC CO., CHICAGO, U. S. A. 



423 



No. 11167. 



11104. PYROMETERS, Thwing Radiation, Portable Type, same as No. 11162, but with scale graduated 



in Centigrade degrees. No A B C 



Range, degrees C 600-1500 



Each $135.00 



11105. PYROMETERS, Thwing Radiation, Portable Type, same as No. 11164, but with double scale; 



graduated in Centigrade degrees. 



~ E F 



600-1500 500-1700 

 1000-2500 1500-3000 



500-1700 1000-2000 

 135.00 135.00 



No. 



Range, degrees C... 



A 



200-800 



500-1700 



145.00 



B 



500-1400 



800-2000 



145.00 



C 



1000-2000 



1500-4000 



145.00 



D 



500-1000 



600-1500 



145.00 



G 



500-1800 

 1200-3000 

 Each 145.00 145.00 145.00 145.00 145.00 145.00 145.00 



11166. CARRYING CASE for Nos. 11162-11165, with leather handles 10.00 



11167. PYROMETERS, Thwing Radiation, Portable Type, for laboratory use, in polished mahogany 



case, with 6-inch scale. Ranges for this instrument are the same as those given under Nos. 



11162 to 11165. 



No A B 



Type single scale double scale 



Each 145.00 155.00 



In ordering, kindly specify scale and range desired. See Nos. 11162 to 11165. 



11168. PYROMETERS, Thwing Radiation, Permanent Type, same as No. 11162, but with wall type 



indicator and ventilated receiving tube for permanent installation. With either single or 



double scales, graduated in Fahrenheit or Centigrade degrees. Write for information as to 



ranges and prices. 

 Note: Thwing Radiation Pyrometers may be secured with other ranges than those listed, and 



with triple range scales if desired. We shall be glad to furnish information and prices upon 



request. Send for special bulletin containing full description. 



QUARTZ APPARATUS, Transparent, see general headings, Crucibles, Dishes, Flasks, etc. 

 RACKS, All Bands, see Supports. 

 RACKS, Milk Test Bottle, see Milk Testing Apparatus. 



RADIO-ACTIVITY APPARATUS 



F2758. ELECTROSCOPE, Box Form. Consists of a metal box about 10x10x10 cm with removable glass 

 front and back. The brass rod carrying the strips of gold-foil is insulated by pure amber, giv- 

 ing the best insulation possible. To obviate radio-active influences, a metal cap is provided to 

 fit over the collar on top of the box and enclose the projecting rod. This electroscope -will re- 

 tain its charge for from 6 to 8 days 4.00 



ELECTROSCOPE, Lind Interchangeable, as used by the United States Bureau of Mines. This in- 

 strument can be assembled to suit the needs of the operator from the parts described below. (See 

 Bulletin 104, United States Bureau of Mines, Chapter V.) 



11200. ELECTROSCOPE HEAD, consisting of a nickel-plated housing containing the leaf system and 

 supporting the reading microscope. It is closed in the front and rear by sheet mica. A fine 

 wire grating makes contact with the mica to ground stray charges. The leaf system is insu- 

 lated by means of an amberoid plug, fitted into a threaded cap, by means of which the leaf 

 may be readily removed. The aluminum leaf is charged by means of a rod set in hard rubber 

 at the right-hand side. Opposite, on the left, is a protector for the leaf when in transporta- 

 tion, which should be withdrawn to full distance when in use. At the bottom of the leaf sup- 

 port is a light spring, to make electrical contact with the interchangeable discharge chambers. 



