BY J. C. BRUNNICH, F.I.C. 47 



amounts of ammonia salts nitrates and nitrates in the air 

 are collected by the rain. The amount of rainwater in 

 nitrogen has for years been carefully ascertained at 

 R-othamstead, and it was found that the average rainfall 

 of 29 inches supplies yearly 3.841bs. of nitrogen per acre, 

 although the rainwater itself contains in an average only 

 4-lOths part of nitrogen per million in the form of ammonia, 

 and 1-lOth part per million as nitrate nitrogen. Similar 

 determinations were carried out elsewhere, and the pre- 

 valent idea that the amount of nitrogen in the water of 

 tropical countries is much higher has not been sustained 

 by the records published by Leather for the rainfall collected 

 in India, at Dehra Dun and Oawnpore. They give almost 

 identical amounts of nitrogen obtained in England, namely, 

 3.25 and 3.41bs. per acre, although the rainfall was 86 and 

 49 inches per annum. Ingle made similar experiments 

 in Pretoria, and found that a rainfall of 24 inches supplied 

 6.581bs. of nitrogen per acre as ammonia, and l.OSlbs. 

 as nitrate nitrogen. I arranged for collection of rain- 

 water at our Roma State Farm, at the tropical Experimental 

 Station at Kamerunga, near Cairns, and at Brisbane, for 

 the past year, and the results so far seem to indicate that 

 our rain is not very rich in nitrogen compounds. 



One of the principal objects of agricultural chemistry 

 is to teach the farmer how he can best maintain the 

 fertility of his soil. Fertility can only be maintained 

 by giving back to the ground that which the crops them 

 selves take away, and this is easily done by the application 

 of artificial fertilizers supplying the essential plantfoods : 



nitrogen, potash, and phosphoric acid. 



A continual process of gain and loss of all the plant- 

 foods, more particularly of nitrogen, is taking place in 

 every soil, and it is one of the main objects of the agri- 

 culturist to encourage every increase of nitrogen, and at 

 the same time reduce its waste to a minimum. A crop of 

 wheat removes from the soil, in the grain alone, from 30 

 to 501 bs. of nitrogen per acre. Of all the fertilizing con- 

 stituents, nitrogen, although so abundant in the air, is the 

 most expensive to obtain, and consequently one of the 

 great aims of experimental chemistry has been to devise 

 a means of utilizing the atmosplieric nitrogen. 



