i68 PLANT PRODUCTS 



Injuries from Chemical Fumes. — Near industrial 

 towns it not infrequently happens that fumes of sulphuric 

 and hydrochloric acids do much harm to fruit trees. Currant 

 bushes appear to be very susceptible to such fumes, but 

 rhubarb is nearly as much injured and beans and potatoes 

 in market gardens are also sometimes damaged. Whilst the 

 removal of the acid vapours is to be desired from every 

 point of view yet for prompt protection something can be 

 done by sprays. At the author's suggestion experiments 

 are being tried with a spray made from one pound of pre- 

 cipitated chalk in ten gallons of water (=i percent.) applied 

 with the ordinary knapsack potato sprayer to the upper 

 surface of the leaves of such plants as show signs of black 

 spots. So far the experiments are very promising. 



REFERENCES TO SECTION V 



Mann, "The Renovation of Deteriorated Tea," Agric. Journ. India, 

 1906, p. 84. 



Coombs, Alcock and Sterling, " Comparative Tests with Mangrove and 

 Wattle Barks," Journ. Soc. Chem. Ind., 1917, p. 188. 



Stevens, " The Function of Litharge in the Vulcanization Process," 

 Journ. Soc. Chem. Ind., 1915, p. 524. 



Davies, " Hysteresis Tests for Rubber," /owyw. Soc. Chem. Ind., 1914, 

 p. 992. 



Stevens, " The Vulcanization of Rubber Agents other than Sulphur," 

 Journ. Soc. Chem. Ind., 1917, pp. 107, 872. 



Eaton and Grantham, " Vulcanization Experiments on Plantation 

 Para Rubber," Journ. Soc. Chem. Ind., 1915, p. 989 ; 1916, pp. 715, 1046. 



Eaton and Day, " Estimation of Free and Combined Sulphur in 

 Vulcanized Rubber, and the Rate of Combination of Sulphur with Plan- 

 tation Para Rubber," Journ. Soc. Chem. Ind., 1917, p. 16. 



Whitby, " A Comparison of the Brazilian and Plantation Methods of 

 preparing Para Rubber," Journ. Soc. Chem. Ind., 1916, p. 493. 



Luff, " Some Aspects of the Synthesis of Caout-chouc," Journ. Soc. 

 Chem. Ind., 1916, p. 983. 



Porritt, " Some Notes on the Raw Materials used by the Rubber 

 Manufacturer," Journ. Soc. Chem. Ind., 1916, p. 989. 



Mann, "Assam Rubber," Agric. Journ. India, 1906, p. 390. 



Fowler, " Bacterial and Enzyme Chemistry," p, 245. (Arnold.) 



Basu, "Orange Cultivation," Agric. Journ. India, 1906, p, 62 ; Wright, 

 " Hevea Braziliensis. " (Maclaren.) 



Joshi, "Orange Cultivation," Agric. Journ. India, 1907, p. 62. 



Knecht, Rawson and Loewenthal, "A Manual of Dyeing." 



Money, " Tea Cultivation." (Whittingham.) 



Crowther and Ruston, " Effect upon Vegetation of Atmospheric 

 Impurities," Journ. Agric. Science, iv., p. 25. 



