294 THE TECHNOLOGY OP SOME OP 



M. Lemaire says that a human body can be preserved with less than fifty 

 centimes of it. The best mode of using it as a disinfectant is a mixture 

 of sulphite of lime and carbolate of lime ; this constitutes " M'Dougall's 

 disinfecting powder." In such a combination the carbolic acid prevents 

 p atrefaction, and the sulphurous acid acts as an ordinary disinfectant, 

 according to Schonbein, in the act of taking one part of oxygen to itself 

 converts another portion into ozone, which produces the disinfecting 

 result. The manufacture of disinfectants has now become a regular and 

 large one, and is carried on by Mr. M'Dougall, near Oldham. He uses 

 the powder to prevent decomposition in stables, cow-houses, or in any 

 accumulations of putrescible matter, and generally for the prevention of 

 decomposition in manures. The solution is employed in dissecting- 

 rooms for the destruction of the noxious smell. A liquid is also pre- 

 pared with carbolic acid and lime water, which is applied to destroy the 

 bad effects of sewers, and acts by stopping the generation of gases in 

 sewer water, or in any accumulation of animal refuse. The liquid is 

 likewise adapted to prevent the decomposition of meat brought to 

 market, or of dead animals. 



Carbolic acid has considerable power of producing colour, and 

 by the action of various chemical agents upon it, valuable blue, 

 red, and yellow dyes have been made. This property may be 

 shown by dipping a piece of deal wood in carbolic acid and then 

 into nitric acid, when it acquires a blue colour ; mixed with 

 ammonia and chloride of lime carbolic acid becomes blue, whilst if 

 mixed with sulphuric acid and added to perchloride of iron, the 

 liquid assumes^a purple hue. Mixed with lime and exposed to the air, 

 it yields rosolic acid, and a rich red colour is produced. An interesting 

 circumstance connected with this fact was mentioned by Mr. Calvert at 

 the Meeting of the British Association at Aberdeen, showing the value 

 of science to commerce. It was noticed that large quantities of the 

 calico sent to India became of a rose colour, and therefore unmarketable, 

 thereby both in the cost of shipping and injury of the article entailing a 

 heavy loss to the manufacturer. Mr. Calvert investigated the matter, 

 and found that the staining was due to rosolate of lime, the formation of 

 which he traced to the following cause. The bales of cotton were pro- 

 tected from wet by a waterproof felt, in the manufacture of which a 

 solution of gutta percha in impure coal naphtha had been used. Under 

 the influence of the warm and damp atmosphere of India, the carbolic 

 acid became volatilized, and coming into contact with the lime in the 

 calico, was converted into rosolate of lime. The discovery of the cause 

 in this manner prevented any similar accident again happening, Eosolic 

 acid is produced by the action of oxalic and sulphuric acids on carbolic 

 acid, and constitutes one of the dyes mentioned as attainable from the 

 latter substance. This action gives rise to the production of a beautiful 

 red solution, but by reason of the alteration which light produced upon 

 it could not for a long time be made available as a dye ; another ob- 



