•CALCIUM CHLORO-HYPOCHLORITE (BLEACHING POWDER). 153 



Properties. — Fused calcium chloride has great affinity for water 

 (i.e. is highly deliquescent) ; in contact therewith it dissolves with 

 evolution of heat. 



Use. — Comstock and Slingerland tried this product, comparatively 

 against other substances, to fight the larvae of Agriotes lineatus (wire- 

 worm), but did not obtain good results. Neither was Waite able to 

 destroy lichens by the use of a 1 per cent solution, whilst Jack recom- 

 mends it in strong doses to kill Equisetum palustre, or poisonous 

 horse-tail, in meadows. 



46. Chloride of Lime (Bleaching Powder), CaCip. — Prepara- 

 tion. — Commercial bleaching powder is a mixture of hypochlorite of 

 lime, calcium chloride, and lime. It is prepared by spreading slaked 

 lime in thin layers on trays laid in a masonry chamber, and passing 

 a current of chlorine over this moist lime, so that a certain amount of 

 unchanged lime remains at the end of the operation, which enables 

 the chloride of lime to keep longer, by protecting it against the car- 

 bonic acid in the air. 



Properties. — Chloride of lime is a white powder with an acrid 

 taste, exhalmg an odour of hypochlorous acid, HCIO ; it dissolves freely 

 in water, leaving a white residue of hydrate of lime. The weakest acids, 

 such as carbonic acid, decompose chloride of lime with disengagement 

 of hypochlorous acid ; chloride of lime must therefore be preserved out 

 of contact with air. The hypochlorous acid which is given off has a 

 very energetic action on organic matter, towards which it acts as an 

 oxidizing agent. This action is more rapid in presence of a mineral 

 acid. 



Use. — Kolbe recommends chloride of lime to destroy poisonous 

 horse-tail {Equisetum palustre). In doses of 352 lb. per acre its de- 

 struction is complete. Chloride of lime has been used to destroy 

 insects. It has been tried against — 



Phylloxera vastatrix, Planch, (phylloxera of the vine). — The 

 Departmental Commission of Herault w^hich examined the processes 

 recommended to combat the phylloxera declared the two following 

 processes quite inefficient : Timbal's, which consisted in burying 

 round about the stocks 20 grammes (306 grains) of chloride of lime, and 

 Dupuis', which consisted in watering each stock with the eau de Javel 

 obtained by mixing 50 grammes of chloride of lime with 12-5 grammes 

 of carbonate of soda in 1 litre of water [in ratio of 5 lb. and 1^ lb. in 

 10 gallons of water]. 



Spilographa Cerasi, F., syn. Trypeta Cerasi (cherry fly). — 

 Taschenberg recommends to prevent cherries from becoming wormy 

 to spread, after the fall of the cherries, around the tree a hot 1 per 

 cent solution of chloride of lime, which destroys the larvae buried in 

 the ground. 



Formica (ants). — Taschenberg proposes for the destruction of ants 

 to spread on their nests a mixture of chloride of lime and of purin, 

 or to mix the earth of the nest with chloride of lime and to water im- 

 mediately afterwards with dilute hydrochloric acid. Cuboni believes 

 that in spraying fields with a milk of chloride of lime they are freed 

 from almost all parasites, and mice and moles are driven away. The 



