EXAMINATION OF AIR 69 



In all these cases the air to be tested is slowly aspirated 

 through the liquid named. Ammonia can be absorbed in 

 pure water and Nesslerized. 



Micro-organisms. See Bacteriology. 



Suspended Matter. Aspirate large quantities of air 

 through small amounts of water in a series of wash-bottles ; 

 evaporate down to aliquot part, mount a drop and count 

 number of particles, or to dryness and weigh residue, which 

 may then be ignited and cooled and re-weighed for non- 

 volatile part. Pouchet's aeroscope. Hesse's apparatus. 

 Sugar filter. Aitken's method. Is composed of animal, 

 vegetable, and mineral matter. Varies in towns from 

 5 to 25 mgr. per cm., or otherwise expressed from 10,000 

 to 2,000,000 particles per c.c. Shaw calculates that 

 400 tons of soot are thrown into the air of London per 

 day. In London 40 cwt. of soot are deposited on each 

 acre of ground per annum, and in Glasgow 22 cwt. in 

 summer and 25 in winter, making 47 in all. 



Carbon Monoxide. From stoves, in water gas, 6 per 

 cent in coal gas, in mines. Affinity for haemoglobin 300 

 times that of oxygen. Kills when blood is saturated up 

 to 60 to 80 per cent. Haldane advises the use of birds 

 and mice as indicators in mines. 



Haldane s Method. Take 5 c.c. dilute blood solution in 

 a clean dry bottle, aspirate in some suspected air, cork 

 and shake for ten minutes, protecting from light. Pour 

 out into a test tube and compare with some of original 

 blood. If CO present, the treated blood will be pink. 

 The test is made quantitative by adding carmine solution 

 to the normal blood until tints equal, and repeating with 

 normal blood saturated with coal gas. 



Spectroscope : spectrum similar to OxyH, but not reduced 

 by Am 2 S. May also be absorbed by copper subchloride 

 in a Hempel's gas burette. 



Oxygen. This may be estimated by combustion with 

 hydrogen, or by absorption in an alkaline solution of 

 pyrogallic acid, or by absorption by nitric oxide. The 

 two latter are done in a Hempel's gas burette, and in the 

 pyrogallic method the carbonic acid is also absorbed and 

 has to be separately estimated and deducted. In these 



