354 EXPERIMENT STATION EECORD. 



position as a scalecide ami fnnjiicide. .Special al tent ion is given to the worlc 

 done in recent yeai'S by the Pennsylvania Station in determining that the proper 

 ratio of lime to sulpluir for concentrated lime-sulphnr mixtures is not constant 

 but varies primarily with the increase in density ; that for orchai'd conditions 

 the best ratio of ingredients is 1 lb. of high grade calcium lime to 2 lbs of 

 sulphur; that the seflimentation of concentrated lime-sulphur in storage is due to 

 exposure to the air, and tlierefore easily remedied by kee])ing in comjiletely filled 

 air-tight vessels; and that the inauguration of a definite system of dilution 

 in the use of lime-sulphur sprays is advisable. 



Notes on a modified soda-Bordeaux mixture, V. Vermorel and E. Dantony 

 iCoiiiiJt. Rend. Acad. 8ci. [Paris], 152 {1911), No. U,, pp. 'J7 2-97. 'i).— The authors 

 describe 2 copper-soda sprays, to which soap was added to increase their ad- 

 hesive or wetting power. 



It was found that when 2 kg. of copper sulphate dissolved in 50 liters of water 

 and 2 kg. of carbonate of soda in 50 liters of water were mixed by pouring 

 all of the carbonate of soda solution immediately into the sulphate solution 

 a precipitate was formed without the liberation of carbon dioxid. The result- 

 ing mixture finally contained insoluble hydrocarbonate of copper and soluble 

 bicarbonate of copper, which the authors call mixture A. If the carbonate of 

 soda is gradually and slowly poured into the sulphate of copper solution, carbon 

 dioxid is evolved and the mixture finally contains insoluble hydrocarbonate of 

 copper and an excess of carbonate of soda ; this is called mixture B. 



If to mixture A 1,000 gm. of white soap free from carbonate and alkalis and 

 very rich in oleate of soda is added, the superficial tension of the mixture is such 

 that 5 cc. forms 85 drops as compared to 66 drops formed from 5 cc. of dis- 

 tilled water used as a standard, and this tension does not vary with time. If 

 to mixture B only 100 gm. of the soap is added the mixture will have a super- 

 ficial tension of 85 drops the same as mixture A, but the tension in B so 

 decreases that at the end of 3 hours it has only 83 drops. When 1,000 gm. of 

 the soap is added to mixture B the tension will be 151 drops immediately after 

 the addition of the soap, 139 drops 20 minutes after, 125 drops 1 hour after, 

 113 drops 3 hours after, 100 drops 6 hours after, and so on until it reaches the 

 85 drop limit of mixture A. This increase in the number of droplets increases 

 the wetting power of the spi'ay, and differs according to the manner of the 

 preparation of mixtures A and B and the subsequent action of their super- 

 ficial tension when the soap is added. This explains, so it is claimed, the 

 divergence of opinion of different investigators as to the value of such sprays. 



On the use of Schweinfurt Paris green for controlling plant diseases, T. S. 

 HoFMAN {Verslag. Larulbouivk. Onderzoclc. Rijkslandhoiiirprocfstat. [Nether- 

 lands], 1911, No, 9, pp. 26-35). — On account of a serious foliage injury which 

 occurred to fruit trees from the use of this substance on certain orchards the 

 author investigated the causes of this injury, and reports the results of his 

 investigations. 



From microscopical and chemical tests of the Paris green the conclusion is 

 reached that the injury was probably due to the use of spray water containing 

 ammonia or ammonium carbonate which rendered soluble appreciable quantities 

 of the arsenic. It was also found that the copper present in the Paris green 

 was inert and quickly changed to cuprous oxid. 



ECONOMIC ZOOLOGY— ENTOMOLOGY. 



Atlas of zoogeography, J. G. Bartholomew, W. E. Clarke, and P. H. Grim- 

 SHAW {[Edmburgh], 1911, pp. 67+XI, pis. 36, figs. 2).— The object of this atlas 

 is to delineate and describe, so far as the state of our knowledge permits, the 



