Sir Robert Robertson 205 



for devising a means of testing the qualities of drinking- 

 water, and for the work he did in pressing for pure 

 supplies. 



Water is such a powerful solvent that it is not at all 

 easy to obtain it in a pure state, and springs which were 

 perfectly good in the past have often been contaminated 

 by the spread of buildings. Take the case of Maidstone, 

 a town which enjoyed the reputation of being very 

 healthy, with an extremely low death-rate and a freedom 

 from infectious disease. In 1897 a terrible plague of 

 typhoid overtook it, but chemists got to work at once, 

 and within a very short time traced the infection to the 

 water-supply. 



In spite of London's excellent supply of well-filtered 

 water, many people long persisted in using old wells, 

 from which the water came up cool and fresh. But these 

 very waters which appealed so strongly to the eye and 

 the palate were often proved to be most dangerous. 

 There was, for instance, the pump near St Bride's Church ; 

 the water from this was famous for its cleanness and cool- 

 ness, yet when analysed it was shown to be poisoned with 

 products of the neighbouring graveyard. Since printed 

 warnings were of no effect the authorities were forced to 

 padlock the handle of this pump. 



The Revenue authorities use quantities of hydro- 

 meters, thermometers, and measuring vessels in their 

 work of gauging and sampling, and it is one of the many 

 tasks of the Government Laboratory to test these before 

 they go out. 



There does not seem to be anything too great or too 

 small to come under the careful eyes of these Government 

 chemists ; their inquiries range from the condition of our 

 telegraph-poles to the genuineness of a postage-stamp. 



In one department you may see a specimen of steel 

 being tested for sulphur. The steel is dissolved in acid 

 and the free sulphur converted into lead sulphate. In 



