10 



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



Q 



No. 1 40. 



No. 142. 



No 152. 



No. 144. 



140. 



144. 



146. 



147. 

 150. 



152. 



No. 146. 



AEROSCOPE, Eettger's, as described in the Journal of Medical Research, Vol. XXII, No. 3, 

 pages 462 and 463. Size of tube, 6 x % inches ?1.25 



AEROSCOPE, Standard, adopted by the American Public Health Association for obtaining bac- 

 teria from air, according to the design of G. L. A. Buehle, of the New York Agricultural Expe- 

 riment Station. Consists of a tube, made of resistance glass to withstand sterilization, drawn 

 down at the lower end to provide a shoulder for supporting a layer of cotton and sand. 

 Length of tube, 110 mm; diameter outside, 15 mm. Complete with selected cork stopper anil 

 bent tube. (See Journal of Agricultural Research Vol. IV, No. 4, for July 19"15) 45 



AGRICULTURAL APPARATUS, see Soil Analysis Apparatus. 



AIR BATHS, see Drying Ovens. 



AIR METERS, see Anemometers. 



AIR PUMPS, BLOWERS, see Blowers. 



AIR PUMPS for Piltration, see Filter Pumps. 



AIR PUMPS for Vacuum and Pressure, see Pumps, Air. 



AIR SAMPLING APPARATUS, Palmer Water Spray, for testing dust and bacteria in air. 

 The apparatus consists of an exhaust fan, connected directly to a universal motor, operating 

 on a 110 volt circuit, which draws air through a venturi meter, the flow through which is 

 indicated in cubic feet of free air per minute on an inclined manometer. The air to be sampled 

 is drawn through a small quantity of filtered, sterilized water placed in the lower neck of a 

 special glass vessel, and the dust and bacteria taken out. This water is then analyzed by stand- 

 ard methods, and calculations made for the number of dust particles or bacteria per cubic foot 

 of air drawn through. The apparatus is enclosed in a mahogany case, 18 x 9 x 6% inches, with 

 a damper on the top to regulate the rate of flow of air. Weight, about 15 pounds. (See Jour- 

 nal of Industrial and Engineering Chemistry, Vol. VI, No. 3, for March 1914; American Journal 

 of Public Health, Vol. VI, No. 1, for January 1916; and Vol. VII, No. 1, for January 1917) 

 125.00 



AIR TESTER, Wolpert's (Carbacidometer), for obtaining the amount of carbonic acid gas in a 

 room by direct readings from the graduations etched on the glass, thus doing away with all 

 computations and tables as in the old forms. Another advantage of this form is that the air 

 of a room may be secretly tested, if desired. Directions and full set of capsules for making 



test solutions furnished with each instrument 4.00 



EXTRA CAPSULES for No. 146. In boxes of 12 capsules (six of each reagent) . . .Per box 1.00 



AIR THERMOMETER TUBE, of glass, with stem 30 cm long. Diameter of bulb 50 mm . . .17 



AIR THERMOMETER TUBE. Same as No. 150, but with capillary stem. Diameter of bulb 



50 mm . .29 



