72 CHEMICAL DISCOVERY AND INVENTION 



of condensed milk all but four were up to the specified standard. 

 The samples of butter and margarine were generally satisfactory ; 

 in six cases the proportion of water was excessive, in three the 

 amount of salt exceeded the specified limit, and three tender 

 samples for Hospital supplies contained boron preservative 

 contrary to the Specification. One sample from a Naval Canteen 

 was found to contain 224 per cent of water and to be mixed with 

 condensed milk. 



The tinned foods examined included peas, kidneys, rabbit, 

 and apricot jam. All were in sound condition, but in tinned 

 peas copper was generally present, and tin was found in some of 

 the other articles. 



In connection with the Board of Agriculture and Fisheries, 

 and the Department of Agriculture and Technical Instruction 

 for Ireland, a large number of samples of milk, cream, and 

 butter are annually examined. 



The examination of the samples of imported butter included 

 in every case the determination of the quantity of water, the 

 examination of the fat as to its purity, and tests for boric acid 

 and added colouring matter. Salicylic acid and hydrogen per- 

 oxide are also occasionally used as preservatives. 



Sixteen per cent of water is allowed by law, but this is occa- 

 sionally, though not often, exceeded. There was no evidence of 

 the presence of fat other than milk fat in any of the samples of 

 imported butter examined. 



In consequence of the poisonous effects of lead on pottery 

 workers a large number of samples of pottery glazes were 

 examined for the Home Office and for other Departments, in 

 connection with the Home Office regulations on the subject. 

 Under these regulations manufacturers are divided into four 

 classes, each of which is subject to a different degree of control. 

 (1) Those who use " leadless " glazes only, a " leadless " glaze 

 being defined as one which does not contain more than one per 

 cent of lead calculated as metallic lead ; (2) those who use only 

 glazes which, tested in the prescribed manner, show no more than 

 two per cent of soluble lead monoxide ; (3) those who use no 

 glazes containing more than five per cent of soluble lead mon- 

 oxide ; and (4) those who enter into no engagement with regard 

 to the quantity or state of solubility of the lead present in the 

 glazes they employ. 



Government Departments now stipulate that the china and 



