2(5 



sugar sweets (candy), and might easily be taken into the mouth as 

 such by a child. There is, however, always the characteristic odour 

 of hydrocyanic acid about potassium cyanide. 



Moisture decomposes potassium cyanide, and it is therefore 

 necessary to keep it in air-tight receptacles. When moistened the 

 substance possesses a secondary injurious action in that it is caustic ; 

 the moisture of the hand is often sufficient to cause it to affect the 

 skin if handled, and likewise fragments which come in contact with 

 cloth or paper burn holes. 



Careful fumigators refrain from handling the substance with the 

 uncovered hand, lest some cling to the skin or become lodged under 

 the nails and subsequently get introduced into the system with food. 

 Care is, of course, always taken to avoid breathing the gas as it 

 rises from the generating vessel ; when mixed with much air, as it 

 immediately becomes when the oloth is removed from the tree, it is 

 not dangerous. 



Sulphuric acid or oil of vitrol (H. 2 S0 4 ), the acid used to liberate 

 the gas, is one of the strongest of acids ; it is an odourless, dense, 

 oily -looking liquid, almost as heavy again as water. When pure it is 

 colourless, but the commercial article is often brownish, owing to the 

 impurities which have fallen into it and become charred. It is 

 intensely corrosive and will burn almost anything with which it 

 comes in contact. Many of the metals are attacked and decomposed. 

 When mixed with water heat is evolved. Painful burns are caused 

 by drops falling on the skin, but as an appreciable period elapses 

 before it burns, the immediate rinsiug of the hands in water will 

 prevent injury. Cloth is burnt even by dilute solutions, the acid 

 gradually becoming stronger by the evaporation of the water. Care 

 must therefore be exercised not to splash the cloth in adding the acid 

 to the cyanide. Most colours are changed to red by the acid ; the 

 immediate application of ammonia to cloth on which it has been 

 spilled will lessen the injury. 



The Cape Government Railway will convey sulphuric acid on 

 certain trains only, and only on the condition that the jars containing 

 the acid are satisfactorily packed in whiting. 



