BORAX. 109 



than white arsenic and consequently much more poisonous to plants. 

 In the composition of arsenical bouillies its formation must be guarded 

 against, or its effects neutralized by the addition of lime. 



Use. — ^The soluble arsenites, such as the salts of potassium, 

 ammonium, as well as the soda salt, have been serviceable owing to 

 their great solubility and their immediate action on insects and in- 

 jurious animals. But this use is, perforce, limited, and then can only 

 be used to poison preparations to be eaten by insects and rodents. 



Disinfection of Seed-Corn. — Boussingault proposed in 1856 to re- 

 place arsenic by arsenite of soda. He recommended to water gradu- 

 ally with constant stirring 2| bushels of grain with a solution of 200 

 grammes of arsenic and 600 grammes of soda crystals in a few litres of 

 water. In an hour the grain was spread out to dry. This method 

 was abandoned long ago. 



Preparations to Kill Locusts. — -In the British Colonies they 

 prevent the migration of locusts by placing in their way bunches of 

 fodder, herbs, or maize stems, steeped in a solution containing per 

 hectolitre 60 grammes of arsenious acid, 60 grammes of caustic soda, 

 and 10 kilogrammes of white sugar or molasses [or 60 oz. (wt.) of 

 arsenious acid, 60 oz. of caustic soda by weight, and 1000 oz. of 

 sugar (wt.) in 100,000 fluid ounces of water]. Drying is prevented 

 by covering the bait with a board or a stone. This bait may be used 

 for other insects. 



28. Borax, NaoB^O^. — Occurrence. — Borax occurs naturally in 

 the lakes of Asia, from which it is extracted by evaporation and crystal- 

 lization. 



Preparation. — By gradually adding 100 lb. of Tuscan boric acid 

 to 125 lb of soda crystals dissolved in 20 gallons of water and then 

 heating by steam. The mixture is concentrated to 30° B., and cooled 

 slowly ; crystals of borax form at the bottom of the receiver. The 

 double borate of soda and lime, or boronatrocalcite, is widely distributed 

 in America ; it is now used to manufacture a large amount of borax 

 obtained by boiling this product with carbonate of soda. 



Properties. — Borax is freely soluble in water. A hundred lb. of 

 borax dissolve in 120 gallons of cold water and the same amount in 

 20 gallons of boiling water. Its solutions react alkaline. Borax is 

 used in medicine as an antiseptic, especially in throat and mucous 

 affections. It is used to preserve meat and putrescible liquors. 

 Werncke found it more active from that point of view than boric acid. 

 Its antiseptic and bactericidal capacity is, however, very weak. Kuhn 

 found that it only acted in 2 per cent solution. Schwartz, however, 

 found that the bacteria of the infusion of tobacco were exceptional, 

 and that a 0-5 per cent solution had already a certain elfect on these 

 microbes. Wenckiewicz found that it had no action on Penicillium 

 glaucum until its solution reached 1"4 per cent. Borax exerts a 

 poisonous action on plants. By watering haricots with a very dilute 

 solution of borax Peligot first induced chlorosis, then death. 



Use. — Borax has been recommended in 5 per cent solution in 

 America against the Peronospora viticola, De By. (mildew of the vine). 

 At that strength it can circumscribe that disease, but its use is not 



