61G REPORT— 1897. 



was xitrt^ ^^^ ^^^ hydrobromic acid ^^^th normal, in the second ^"(jth and ^ijth 

 normal respectively. When the equation of the second order, viz. — 



was employed for calculation with these experimental results, it gave no approach 

 to a constant value for k ; but when they were substituted in the integrated form 



of — = A (a — a;)* — the equation of the 4th order— the first series gave a mean 



value of 00113-^10*, and the second series 0-00119-=-10'. The agreement is as 

 close as could be expected from the experimental method. 



These experiments confirm the conclusion that the reduction of bromic acid 

 takes place in stages, the first of which consists in the formation of bromous and 

 hypobromous acids. It further shows that these acids, which have never been 

 isolated, are excessively unstable in presence of hydrobromic acid, and points to a 

 method for their preparation which we intend to investigate. 



TUESDAY, AUGUST 24. 



The following Papers were read : — 



1. On the Coinjjosition of Canadian Virgin Soils} 7?y Frank T. Siiutt, 

 M.A., F.I.C., F.C.S., Chemist, Dominion Experimental Farms. 



The soil investigations carried on in the laboratories of the Dominion Experi- 

 mental Farms at Ottawa have included the chemical and physical examination of 

 certain typical virgin (uncropped and unmanured) soils. The samples were carefully 

 collected in the various provinces of the Dominion, and may be regarded as types 

 or representatives of areas of fair uniformity and considerable magnitude. 



Data respecting all the soils analysed are not included in this Paper, and only 

 the more important elements of fertility of these here presented have been dis- 

 cussed. The majority of the samples considered are surface soils, but in a large 

 number of instances the results obtained upon their respective sub-soils have been 

 inserted. 



The exact value of an ordinary soil analysis in ascertaining the fertility or 

 productiveness of a soil is considered, and while it is admitted that hot hydro- 

 chloric acid (sp. gr. 1'115) dissolves larger amounts of mineral plant food than are 

 of immediate availability to crops, it is pointed out that a knowledge of the 

 ' maximum ' amounts shows decisively deficiencies, if any exist, and thus indicates 

 lines for rational and economic treatment of the soil with fertilisers. Further, 

 it is held that soils possessing large ' maximum ' amounts will in all proba- 

 bility prove more fertile than those showing smaller percentages, the climatic 

 influences in both cases being equally favourable. 



The diagnosis of a soil as regards productiveness cannot be made from chemical 

 analysis alone, even if such includes a determination of the so-called ' available ' 

 plant food. The phy.sical condition of the soil, drainage, rainfall, mean tempera- 

 ture, sunshine, &c., are factors that must receive careful consideration. 



Pot or plot experiments with various fertilisers are at present the only means 

 of gaining reliable or accurate knowledge of a soil's needs, but the incentive given 

 by Dr. Dyer in 1894, in publishing his results by the 1 per cent, citric acid solution, 

 has resulted in many agricultural chemists on this continent directing their atten- 

 tion to this important subject, and the probabilities are that, ere long, laboratory 

 methods will be agreed upon for determining available plant food in soils. 



The standards of fertility, as suggested by Dr. Hilgard, of the California Experi- 



» Published in extenso in the Chemical News 1897, Oct. 15, et se^. 



