ABSTRACTS; 



323 



Indigofera, Notes on. By D. Pram and E. Baker (Jo urn. Bot. 

 470, pp. 60, 67 ; 2 1902 ; and 471, pp. 136-144 ; 4/1902).— An attempt 

 to elucidate the synonymy, pre- and post-Linna3an, of the indigo-yielding 

 species.— G. S. B. 



Influence of different Kinds of Manure on the Quality of 

 Starch. By Ch. Guffroy [Ann. Agr. p. 442 ; September 1901). 



C. H. H. 



Influence of Light, Altitude, Moisture, and Temperature on 

 the Growth Of Plants. By M. Charabofc (Ann. Agr. p. 383 ; August 

 1901). — Richness in scent of Lavender increases with altitude, dependent 

 on more light, drier air, and lower temperature ; the first two factors act 

 in the same direction, the last has a contrary action. Dry air favours the 

 formation of scent, while it makes the chlorophyll action more active. 



C. H. H. 



Insecticides and Fungicides: Chemical Composition and 

 Effectiveness of certain Preparations. By J. K. Haywood (U.S.A. 

 Dep. Agr., Farm, Bull. 146, pp. 1-15; 1902). — This paper is a digest 

 of a somewhat elaborate study of the various insecticides found in the 

 American markets, clearly setting forth the desirability of ascertaining 

 the composition and value of such compounds before purchasing. — R. N. 



Insecticides, Nature and Use of certain. By J. L. Philipps 

 and H. L. Price (U.S.A. Exp. Stn. Virginia, Bull. 97). — These poisons 

 are divided into food or internal poisons, contact poisons, tracheal poisons. 

 Of the mineral food poisons Paris green is the best known of arsenical 

 poisons (an aceto-arsenite of copper, with about 58 per cent, arsenious 

 -acid). Safest to add lime in, say, twice the volume to avoid possibility of 

 burning foliage. Used at the rate of 1 lb. to 100 gallons for Apple, 

 1 lb. to 300 gallons for Peach. London purple, a by-product in manu- 

 facture of aniline dyes, varies in composition, is an arsenite of calcium 

 used in like proportion as Paris green with twice the weight of fresh 

 slaked lime. There are several other forms of arsenic used. Among the 

 l)est are green arsenoid, or Scheele's green, an arsenite of copper, with 

 about 62 per cent, arsenious acid, used as Paris green : being more finely 

 •divided and bulkier remains in suspension better, and costs less. 

 Arsenate of lead, no fear of injuring foliage, but costs more than Paris 

 green (7^- oz. acetate of lead dissolved in one pailful of warm water, in 

 wooden pail, 2| oz. arsenate of soda in a second pail : when dissolved 

 pour together into 100-gallon tank of water and stir briskly). Nitrate of 

 lead may be used instead of acetate of lead, thereby saving in cost, yet 

 oqual in value. 



Of vegetable poisons hellebore is employed : 1 oz. to 1 gallon water, 

 or sprinkled diluted with equal parts of lime or flour and dusted on the 

 foliage whilst wet. Used for Gooseberry and Currant caterpillars. 



Of the contact poisons paraffin has been used alone for San Jose and 

 other bark lice, also mechanically mixed with water at 20 per cent., but it 

 was considered that soap solutions were superior. 



Paraffin emulsion : ^ lb. whale-oil soap dissolved in 1 gallon of water, 



Y 2 



