726 EXPERIMENT STATION RECORD. [Vol.40 



The results indicated that the carbid waste was practically as effective as 

 calcium carbonate, whether applied one month before sowing or at the time 

 of sowing, and that when it is thoroughly disintegrated it may be applied in 

 fairly large quantities without injurious effects. The main difficulty attending 

 the use of the material is due to its wet condition. 



Magnesium and sulphur nutrition of plants (Arkansas Sta. Bui. 158 (1918), 

 pp. 24, 25). — Observations made in the greenhouse with soy beans grown on 

 Orangeburg fine sandy loam soil to study the effect of magnesium compounds 

 on the oil content of the seed are briefly described. 



Additions of magnesium carbonate and oxid are said to have resulted in an 

 increase of about 18 per cent in the air-dry weight of the plant, and a slight 

 increase in the yield of seed, while the fat content of the latter increased 

 about 10 per cent with the carbonate and 8 per cent with the oxid. The in- 

 creased production of fat amounted to 2S and 20 per cent, respectively. 

 Magnesium in plant parts other than the seed showed an increase of about 50 

 per cent, while the calcium content decreased. This is thought t<> support the 

 view that any influence magnesium absorption may exert unpon the composi- 

 tion of the seed is associated with chlorophyl formation and carbon dioxid 

 assimilation. 



Contribution to the agricultural study of iron, A. Monnikk and L. 

 Ktjczynski (Arch. Sci. Phys. et Nat. [Geneva], ^3 (1918), pp. 66-08; ab». in 

 Chem. Abs., IS (1919), No. 1, p. 52).— A study of the solubility of the iron in 

 soils and of the changes which ferrous and ferric compounds undergo In the 

 soil is reported. 



The results indicate that the iron normally present in soils is Insoluble. This 

 explains the marked effect of adding small amounts <>f iron compounds to the 

 soil. This effect is produced, however, only when the iron compound is placed 

 near the roots. Otherwise it is rendered Insoluble before it can be absorbed by 

 the plant. Potassium ferrocyanid was found to be toxic even in very small 



amounts in the soil. It underwent a double iK mpositon, a part of the potash 



being absorbed by the soil and potassium ferricyanid passing Into the filtrate. 



Report on commercial fertilizers, 1918, E. II. Jenkivs and E. M. I'.aiivy 

 (Connecticut State Sta. Bui 209 {1918), /</>. 128-1 70). — This reports the results 

 of the actual and guarantied analyses of 466 Official samples of commercial 

 fertilizers and fertilizing materials collected during 1918. A number of mis- 

 cellaneous materials and waste products from different sources were also 

 analyzed as usual. 



Commercial fertilizers in 1917-18, G. S. Fraps (Texas Sta. Bill 233 (1918), 

 pp. 3-25). — This reports the results of the actual and guarantied analysis of 

 official samples of commercial fertilizers and fertilizing materials collected dur- 

 ing the year ended September 1, 191S. A list of the brands registered for sale 

 in the State during the season is also included. 



AGRICULTURAL BOTANY. 



A sketch of botanical activity in the District of Columbia and vicinity. 

 P. L. Rickek (Jour. Wash. Acad. Sci., 8 {1918), Nos. U, pp. +87-498; 15, pp. 

 516-521). — The first section of this contribution deals with the persons who 

 have been active in connection with different phases of botany in the District 

 of Columbia. The second gives a list of relate. 1 publications. 



The cytology of the myxomycetes with special reference to mitochondria. 

 N. H. Cowdey (Biol. Bui. Mar. Biol. Lab. Woofo Hole, 35 (1918), No. 2, pp. 

 71-94, pis. 3). — The author reports a search for mitochondria In 10 slime molds 



