FIKLL) CROPS. 945 



per (viit. TIk' hick of iiiagiu'sia in the plant I'lxid nianift'situd itself in wniall and many 

 undeveloped grains, but it was noticed that the haulms could develop in spite of an 

 insutticient supply. 



The results of the sulphur series show in some cases an increase in sulphur content 

 of the plants associated with an increase of this element given in the fertilizer, but 

 as in the Ciise of nitrogen and phosphoric acid it was also found constant. In this 

 <'onnection tiie grains showed only slight variations. 



The influence of varying quantities of water on the composition of the plants way 

 studied and the results show that in water and sand culture different quantities of 

 water caused great variation in the nitrogen and potash content of the plants, but 

 where the plants were grown on ordinary agricultural soils only the nitrogen figures 

 varied widely, the potash and lime content varied less and the amounts of phosphoric 

 acid, magnesia, and sulphur varied least. The results further indicate that generally 

 an increase in the moisture content of the soil causes a relatively greater increase in 

 the weight of the stems and leaves than in the weight of the grains. It was further 

 noticed that close planting tended to decrease the content of plant food elements, 

 especially in the case of nitrogen. It is stated that the season also is a strong factor 

 affecting the composition of the oat plant, a favorable season usually lowering the 

 figures for nitrogen and phosphoric acid and increasing them for lime. The smallest 

 changes were noticed in the content of phosphoric acid and magnesia. 



On the basis of the results of this investigation, the author draws the following 

 conclusions: (1) When, in case of oats, the supply of an element of plant food is 

 increased, this particular element is taken up and assimilated bj' the plant in increas- 

 ing quantities, and the percentage content in the plant is also increased, except that 

 nitrogen and phosphoric acid often remain constant under these conditions. ( 2 ) When 

 an increase in a certain element of plant food increases the yield, the percentage con- 

 tent of the remaining elements in the i^lant is necessarily lowered, although in several 

 instances in this work phosphoric acid and sulphur remained constant. (3) In case 

 of a weak and poor development of the plants, a low percentage content is to be 

 expected only of the element which is present in smallest quantity in proportion to 

 the needs of the plant. Other elements, although present in the soil in barely suf- 

 ficient quantities, may show a more or less high percentage content in the plants 

 produced. 



From the results of his work, the author gives the following method for determin- 

 ing the element which is present in the plant in minimum quantity: The percentage 

 content as shown by the analysis is compared with the average and mininmm con- 

 tent of oats. In general, the fertilizing ingredient whose i^ercentage is farthest below 

 or least above the average figure and nearest the figure representing the minimum 

 content is present in minimum quantity. The author believes that it is possible to 

 determine by chemical analysis of oats the fertilizing ingredient which was present 

 in minimum quantity in the soil producing them, and the ingredients present in 

 larger (quantities, and the results thus obtained will permit of probable deductions as 

 to the relative fertilizer needs of the soil. He explains, however, that the indications 

 are always to be regarded with some doubt. He advises that the green i)Iant be 

 used for analysis. In conclusion the "normal" figures as obtained by the author in 

 his work are sunnnarized. — f. w. woll. 



Studies on potatoes, A. pETicinr.vxx (Bui. List. Chim. ct Bad. Gcmblon.r, 1901, 

 Xd. 70, pji. 10). — The results of variety tests are reported and conclusions concerning 

 the relation between the chemical composition of the tubers and their cooking qual- 

 ities are given. The cultural treatment is descril^d and the different varieties classi- 

 iied according to their starch content and their value for the table. 



Variety tests with potatoes, C. Fri'wirth {FiMvig'i< Laixlir. Ztg., 50 (1901), 

 No. 4, pp. leo-ios). — A report <tn testing 47 varieties in 1899, and 49 in 1900. 



The necessary qualities of potatoes for the manufacture of alcohol, with 



