240 Summary of Agricultural Experiments, [june, 



poisonous to crops growing on land to which it might be applied. The 

 sulphided lime 'was found to have some fungicidal power, 10 per cent, 

 solutions preventing spores from germinating, but its fungicidal pro- 

 perties did not seem strong enough to give it any practical value. The 

 solutions of carbonated lime had no appreciable effect on the germina- 

 tion and rate of growth of the spores. 



Composition of Soot (Jour. Agric. Science, Vol. Hi., Pt. 4, December, 

 19 10). — The value of soot as a manure depends upon the ammonia con- 

 tained in it, as well as upon its beneficial effect on the texture of the 

 soil, and its power of diminishing the attacks of slugs and snails. The 

 quantity of ammonia or nitrogen in soot, however, varies greatly, and 

 this investigation was carried out by Mr. H. W. Harvey, 

 of Cambridge University Department of Agriculture, in order 

 to throw some light on the relation between the general charac- 

 teristics of soot and its nitrogen content. One sample of soot from a 

 kitchen chimney was found to contain n'o per cent, of nitrogen, and 

 weighed 9 lb. per bushel, loosely packed. In the other samples from 

 dwelling-houses the nitrogen varied from 5*5 to 27 per cent., and the 

 weight from 185 to 33 lb. per bushel, the lighter soots usually con- 

 taining the greater proportion of nitrogen. Thus the general opinion 

 of farmers that a light soot is best is well borne out. Owing to this, 

 the safer method would be to buy soot by volume instead of by weight, 

 as the buyer will then be likely to get an approximately constant 

 quantity of nitrogen per bushel. Most of the samples mentioned 

 contained approximately 1 lb. of nitrogen per bushel, and the soot 

 would be worth about 6d. per bushel for its fertilising value alone, apart 

 from its action on the soil or on insect pests. 



A sample of flue dust from a 40 ft. boiler shaft contained only 0*5 per 

 cent, of nitrogen. This sample was of a reddish colour, but the colour 

 alone could not be relied upon to show its nature, since a sample from a 

 kitchen chimney with 5*4 per cent, of nitrogen also had a distinctly 

 reddish tinge. Flue dust from the Cambridge Rubbish Destructor, 

 similar to that from the London Destructors which is used extensively 

 upon the hop-fields of Kent, contained no nitrogen, and was composed 

 almost entirely of inorganic matter, mostly oxides of aluminium and 

 iron with calcium carbonate. 



Calcium Cyanamide and Nitrate of Lime (Lanes. C.C. Educ. Com. 

 Agric. Dept., Farmers' Bui. No. 20). — The four nitrogenous manures, 

 nitrate of soda, sulphate of ammonia, calcium cyanamide or nitrolim, 

 and nitrate of lime, were used in 19 10 on oats, mangolds, and potatoes. 

 The nitrogen contained in each was as follows : — 



Sulphate of ammonia (24 per cent, ammonia) ... ... 20 per cent. 



Nitrate of soda (95 per cent, purity) ... ... ... 15^ 



Calcium cyanamide ... ... ... ... ... 18 to 20 ,, 



Nitrate of lime ... ... ... ... ... ... 13^ 



They were applied in quantities containing approximately equal 

 amounts of nitrogen, and the results appeared to show that the same 

 amount of nitrogen in any of the four forms is equally effective for 

 crop production. The extension of the use of the two new manures will 

 therefore depend largely upon the price per unit of nitrogen contained 

 in them. Both are less convenient to handle than the older manures, 

 calcium cyanamide being very light and dusty, and liable to cause injury 



