Vol. X. No. 242. 



THE AGRICULTUKAL NEWS. 



249 



JSlanif'oba rubbers (M. dichotoma and M. piaiihyensis), 

 and wit.h San Francisco rubber {31. heptaphylla). 



Fair amounts of Lagos and Central American 

 rubber have been planted in Germ:ni East Africa, but 

 there is no great future for these species, i'he indica- 

 tions are better for Para rubber (Hecea brai^ilievsis), 

 but the conditions are not favourable, on account of the 

 possibility of drought. It has bi'cn advised that where 

 irrigation is possible, Hevea may be planted amung 

 Manihot. 



Other rubber j)lants with which trials are being 

 made are: Landoiphia Stolzii, L. dondeensis, Cryp)- 

 tostec/ia graiidiHora_ Clitandra /.■iiirnandjavic((, 

 jMuscarenhasin clustica and Flciii^ Scldechteri. 



The Work of Bacteria in the Soil. 



A paper describing investigations in relation to 

 this subject is abstracted in the E.rjicriinent Station 

 Record, Vol. XXIV, p. 826. In the experiments, it was 

 shown that the repeated cultivation of land on which 

 croj s were not allowed to grow caused a material 

 increase of the number of bacteria in the soil, the chief 

 increase being in the summer months. Additions of 

 phosphates and ])otash liid nos aj)[iarently affect the 

 number o( bacte'ia present, but ihey hastened the 

 breaking down of organic matter. Organic substances 

 such as straw, sugar and starch, and similar substances 

 containing nitrogen, had the same effect as repeated 

 cultivation, on the number of organisms: while soduim 

 nitrate and ammonium sulphate, like phosphates and 

 potash, did not exert any material influence. 



The work was further concerned with investiga- 

 tions in relation to the fixation of ninngen with the aid 

 of legurrinous ])lants. In this, the important fact was 

 elucidated that such plants use the nitrogen in com- 

 pounds in the soil, and that in the air, simultaneously; 

 that is to say, there is no large consumption of the 

 nitrogen in the soil by leguminous plants, before they 

 commence to form nodules. 



Alcoliol for Motive Power. 



The Journal of the Bepartriunit of Agricidture 

 of Victoria, for February 1911, contains an article on 

 this subject, in which it is pointed out that, both in 

 CJermany and in America, proof has been obtained that 

 alcohol as a motive power, as regr.rds equal bulks, is 

 little inferior to gasolene. Alcohol po^sesses many 

 advantages over gasolene: it bears higher compres.sion 

 without premature explosion; it is cleaner to use; its 

 combustion gives exhaust gases that are not as objec- 

 tionable as those from gasolene; it possesses a le.ss 

 inflammable vapour than that of gasolene, except where 

 it is closely confined: and its production is practically 

 unlimited, and is possible to a large extent from what 

 is at present waste matter. 



After pointing out the facts on which the produc- 

 tion of alcohol from starchy materials depends, reference 

 is made to the circumstance that .S(),000,000 gallons of 

 alcohol have been produced from potatoes in Germany, 

 in the course of one year. The types of distilling app.i- 

 ratus employed in that country vary, but they are 



usually of the continuously working, column form. 

 Brachvogel's Industrial Alcohol is recommended as 

 a work to be read by all who are interested in the 

 manufacture of alcohol from agricultural products. 



The article concludes by making reference to the 

 many uses of denatured alcohol, and points out that 

 its main employment in future will doubtless depend 

 largely on its successful use as liquid fuel for industrial 

 motors. This, however, awaits the evolution of the type 

 of motor that will make use of alcohol to the best 

 advantage. 



Loss and Gain of Nitrogen in Cultivated Soils. 



A brief account of the work of A. Koch (an inves- 

 tigator whose name is also mentioned on \):igQ 247 

 of this issue of the Agricultural Neivs), with regard to 

 the utilization of certain nitrates by soil bacteria, is 

 contained in the Experiment Station l\ecord of the 

 United States Department of Agriculture, Vol. XXIV, 

 p. 140. 



As would be expected, it was found that, in very 

 damp soils, free nitrogen is yielded by nitrate of soda, 

 whereas, if the soil is well drained and aerated, the 

 nitrate is used by the bacteria for forming albuminoid 

 nitrogen. 



With regard to carbohydrates as a source of energy 

 for the fixation of nitrogen, it was found that cellulose, 

 as well as sugar and starch, is effective in this relation. 

 In the actual experiment to investigate the matter, 

 100 gm. of earth, mixed with paper as a source of 

 cellulose, and inoculated by means of stable manure, 

 was found to yield 29 mg. of additional nitrogen. 



The Formation of Prussic Acid duricg- Germina- 

 tion. 



In the Ihdlctli) of the Bureau of Agricultural 

 Intelligence and of Plant Diseases, of the International 

 Institute of Agriculture, for November 1910, p. 42, 

 there is presented an abstract of results that have been 

 oblaintd iu an investigation of the formation of prussic 

 (hydrocyanic) acid during the germination of seeds of 

 (juinea corn and of Hax {Linum wsitatissimuni), both 

 iu the light and in the dark. 



The experiment showed that there is such a form- 

 ation under those conditions, in both cases, and that 

 the amount of acid produced increases as germination 

 continues, up to a certain limit, beyond which there is 

 a decrease. During equal periods of germination in 

 the light and in the dark, the quantity of acid formed 

 is smaller in the latter case. 



Further, plants kept in the dark and watered vvith 

 a 2-per cent, solution of glucose gave a larger proportion 

 of prussic acid than those, kept similarly, which did not 

 receive the glucose. It is thus suggested that an 

 important part is taken by carbohydrates in the forma- 

 tion of prussic acid during germination. 



From one point of view, the experiments are of 

 interest in relation to the poisoning effect of unripe 

 sorghum, owing to its containing prussic acid (see 

 Agricultural N^eivs, Vol. X, p. 123). 



