68 PROCEEDINGS OF SECTION B. 



gave results which were borne out accurately when applied to 

 ships' holds, and it struck me at the time that the method would 

 be of some value in deciding ventilation questions. 



For this purpose oxygen gas could be conveniently employed 

 since it has practically the same density as air, and would behave, 

 so far as ventilation is concerned, just as if it were air, while at the 

 same time providing a means of accurately determining air dis- 

 placements. With a small model the ventilating arrangements 

 of any building for instance could be tested by admitting a known 

 quantity of oxygen gas and determining the amount of original 

 air displaced from its various portions. 



Another use for gases which will probably receive more 

 attention in the future relates to the appUcation for destruction 

 purposes of the force liberated by many gases and vapours on 

 explosion with air. We are all aware of the destruction wrought 

 in coal mines by gas explosions, and that on innumerable occasions 

 dwelling-houses and factories have been shattered by the same 

 means. I think that this explosive force might be turned to 

 account in this country to aid in the destruction of rabbits and 

 their burrows by displacing the air in the burrows by an explosive 

 mixture of, say, petrol and air, and then firing the mixture. I 

 have got as far in the matter as to interest a friend to construct 

 a machine, but we have not yet had an opportunity of testing it. 

 It is true that at the present time various inflammable vapours, 

 such as carbon bi-sulphide are charged into the burrows and 

 sometimes ignited, but it seems to me that if the matter were 

 pursued further and as much as possible of the air of the burrows 

 displaced by an explosive mixture much more effective results 

 would be obtained than has been the case hitherto. 



3.— THE ANALYSIS OF LIQUEFIED AMMONIA. 

 By W. HEBER GREEN and B. D. STEELE, Melbourne. 



Abstract. 



The authors point out that the impurities present may be of three 

 kinds : — ■- 



(1) Permanent Gases. 



(2) Non-gaseous soluble substances. 



(3) Insoluble impurities held in suspension. 



The first kind may be readily determined by the ordinary 

 method of absorbing the ammonia in water and collecting the 

 permanent gases in suitable measuring tubes. 



The second kind are usually estimated by the so-called 

 '-' evaporation test," but the results so obtained are only approxi- 

 mate, and give no guarantee as to the absolute purity of the lique- 

 fied ammonia. For making this absolute determination the 

 authors have devised a method which consists of absorbing a 

 known amount of the ammonia in a weight quantity of sulphuric 



