FIELD CEOPS. 231 



temperature slightly above freezing is best for seed potatoes, but for culinary 

 purposes a moderately diy, well-ventilated cellar or vault, with a temperature 

 ranging between 38 and 42° F. is preferable." 



The determination of sulphur and chlorin in the rice plant, Alice R. 

 Thompson {Haivaii Sta. Rpt. 1912, pp. 6//-7S). — This paper has for its purpose 

 to show the sulphur and chlorin " content of the parts of the rice plant at 

 3 stages of growth, and to determine the effect, if any, of fertilizer on the 

 sulphur and chlorin composition of the plant grown in natural soil conditions 

 and in sand cultures; also to determine the amounts of sulphur and chlorin 

 contained in the rice field soil and water. The phosphoric acid content of the 

 plant has been given in a previous publication [B. S. R., 24, p. 635]." 



The method of analysis for total sulphur was Hart and Peterson's (E. S. R., 

 25, p. 519) modification of Otibome's method (E. S. R., 13, p. 521). It was 

 found in making the sulphur determination that especial care must be taken 

 with reference to the influence which gas burners have on the results. It is 

 advisable to make the sulphur determination in a room shut off from gas 

 fumes, and to fuse and boil over alcohol lamps. 



The mineral sulphur was determined by stirring the sample with 100 cc. of 

 cold 1 per cent hydrochloric acid solution, and allowing it to stand an hour 

 before filtering. When the starchy materials were examined, the sample was 

 first boiled in the hydrochloric acid solution to render it soluble. Tliis pro- 

 duced no hydrolysis of the sulphur. Chlorin was determined by the Volhard 

 method. " The samples of rice plants for this work were collected March 23, 

 April 19, and May 15, 1912, 10 clumps of the plants being selected from each 

 of 2 plats at the trial grounds. The first series of plants was taken before the 

 flowering and divided into foliage and roots for analysis. The second series was 

 taken at the time of full-stage flowering and divided into panicles, leaves, 

 stems, and roots. The third series was taken at maturity and divided Into 

 grain, chaff, leaves, stems, and roots." 



In studying the composition of the rice plant at the first harvest, 2 plats were 

 used, one unfertilized check plat, the other fertilized with ammonium sulphate, 

 superphosi^hate, and potassium sulphate. At this time the percentage of sulphur 

 is higher than at any other period of growth, and is about equally distributed 

 betv/een the foliage and roots. The unfertilized plat showed about 0.1 per cent 

 higher than the fertilized plat, but this is probably due to the larger size and 

 greater growth of the plants which were fertilized. " The percentage of min- 

 eral sulphur is highest in the roots, being almost 4 times as high in the roots 

 as in the foliage, but it is much less than the total sulphur, showing the forma- 

 tion already made of organic sulphur in the plant. Chlorin is also highest at 

 this first period and, like sulphur, is found in largest percentage in the roots." 



At the second harvest there was practically no difference in the composition 

 of the plants, although the fertilized plants were much larger and heavier. 

 "The percentage of sulphur in the total plant has decreased from the first 

 period, the leaves having the highest content in sulphur, the stems the lowest. 

 No mineral sulphur was found in the panicles, but this form was relatively high 

 in the roots and leaves. Chlorin had also decreased in percentage amount and 

 was quite low in the panicles and high in the roots. At the third harvest the 

 fertilizers show no effect on the composition of the plant. Total sulphur is 

 very small in the stems and chaff, and about 0.23 per cent in the other parts of 

 the plant. Mineral sulphur is found only in the roots, showing that the plant 

 had used up the mineral sulphur in the formation of organic material. Chlorin 

 is practically absent from the grain, though high in the stems. 



" Mature rice plants from plats under different fertilizer conditions [i. e.. 

 check; sulphate of potash, superphosphate; ammonium sulphate, sulphate of 



