THE RAPID AGEING AND FIREPROOFING OF WOOD. 297 



be mingled in sufficient proportion with other gases which do not 

 burn easily, in such a way that the disorganisation of bodies by 

 heat will be reduced to a simple calcination without production 

 of flame. Salts which are volatile or decomposable by heat, but 

 not combustible, like certain ammoniacal salts, afford excellent 

 results. 



Numerous processes have been recommended for combating the 

 inflammability of organic tissues, some consisting in external 

 applications, others in injection under a certain pressure of saline 

 solutions. 



By simple superficial applications only illusory protection is 

 attained, for these coverings, instead of fireproofing the objects 

 on which they are applied, preserve them only for the moment 

 from a slight flame. Their power of resistance to the fire being 

 of only short duration, these coatings scale off or are rapidly 

 reduced to ashes, and the parts covered are again exposed. It 

 often happens, too, that such coatings have disappeared before 

 the occurrence of the fire, so that the so-called remedy becomes 

 injurious from the false security which it occasioned. 



We will cite some formulas still recommended. They are 

 applied — 



(1) By immersion or imbibition; 



(2) By application of successive coats by mean of a brush. 



1. For immersion or imbibition the following solution is 

 advised: — Ammonium phosphate 100 grammes; boracic acid 10 

 grammes per litre, or ammonium sulphate 135 grammes; sodium 

 borate 15 grammes, boracic acid 5 grammes per litre. For each 

 of these formulas two coats are necessary. ^ 



2. For application with the brush, the three following composi- 

 tions are the best : — 



{a) A mixture of hot sodium silicate 100 grammes, Spanish 

 white 50 grammes, glue 100 grammes. 



(h) For first application — hot water 100 grammes; aluminium 

 sulphate 20 grammes : second application — hot water 100 

 grammes; liquid sodium silicate 50 grammes. 



(c) First application, two coats hot of — water 100 grammes ; 

 sodium silicate 50 grammes : second application, two 

 coatings of — boiling water 75 grammes, gelatine white 

 200 grammes ; work up with asbestos 50 grammes, borax 

 30 grammes, and boracic acid 10 grammes. 



^ 1 gramme = (about) 15| grains troy ; 1 litres a little less than 1 quart. 

 VOL. XVII. PART II, U 



