﻿8 METHODS FOE THE DETERMIXATIOIs^ OF 



tion are added to the diluted absorbent material, and also 5 c. c. of 25 

 per cent sulphuric acid, and the boiling continued for five minutes. 



Method I. 



A. Total oxidizable matter. In this method the total oxidizable 

 matter in air is determined hj aspii-ating a known volume of air 

 through 100 c. c. of twice distilled water, contained in a Pettenkofer 

 absorption tube, and then determining the amount of oxygen consumed 

 bj this absorbent as compared with the same amount of the water 

 before the experiment, the difference between the two results repre- 

 senting the amount of reduction produced by the organic matter in the 

 volume of air aspu-ated. The results obtained by this method are 

 given in Table II ; the form of apparatus employed is shown in Fig. 1. 



B. Free and albuminoid ammonia. The free and albuminoid am- 

 monia is determined in the 100 c. c. of twice distilled water, used as 

 the absorbent material in this method, and through which a known 

 Tolume of air has been aspirated, and the amount of ammonia found 

 in the same quantity of the water before using is deducted from the 

 results of each of the determinations. The results obtained by this 

 method are shown in Table I ; the form of the apparatus is the same as 

 that shown in Fig. 1. 



Method II. 



A. Determination of the gaseous and dust-form of organic matter 

 *in air, according to the method of Uffelmann. A small Erlenmeyer 

 £ask, of 100 c. c. capacity, and closed with a rubber stopper 

 having two openings, contained the absorbent material which in 

 this method is 25 c. c. of ^ solution of permanganate of potash 

 acidulated with sulphuric acid. The openings in the rubber stopper 

 of the flask carry two short pieces of glass tubing ; the one is connected 

 .at its upper extremity with a small globe-shaped glass tube containing 

 freshly ignited 'asbestos or glass-wool, and the lower extremity of the 

 tube extends nearly to the bottom of the flask. The other glass tube 

 is bent at right angles just above the stopper, and terminates just 

 below the inner edge of the stopper. The other end of this tube 

 is connected with the aspirator. 



The gaseous form of organic matter is retained in 25 c. c. of perman- 

 ganate solution in the flask. Its amount is determined by diluting 

 the permanganate solution with 75 c. c. of twice distilled water and 

 boiling in the ordinary manner, deducting the amount of oxygen con- 

 sumed by the 75 c. c. of water from the end-result 



