206 Master Minds of Modern Science 



another room you may notice a worker testing a small 

 piece of painted wood to find out whether the contractor 

 has laid on three coats of paint as he had agreed to do or 

 only two. It may be mentioned that in the case which 

 came under the writer's notice it was speedily proved 

 that there were only two coats, and the contractor had 

 a bad quarter of an hour. 



In still another room the writer saw a shelf full of soda- 

 water bottles ; on inquiry it was learned that these were 

 filled with sea-water. There were samples taken from the 

 seas of all the world, and they were being tested for the 

 quantity of salt contained in each. There is, for instance, 

 far more salt in the North Sea than in the Baltic, and 

 more in the Atlantic than in the Mediterranean. 



Knowledge of the salt content of these various samples 

 helps the chemists and others to determine the drift of 

 currents, the rate at which the spawn of fish is carried, 

 and, to some extent, the amount of ' plankton ' — fish- 

 food — which exists in various seas or oceans. 



One more achievement which is well worth recording is 

 the recovery of the radium used during the Great War. 

 Radium, as we all know, is very scarce and costly. At 

 comparatively small expense these chemists have suc- 

 ceeded in restoring to its original state no less than 

 ninety-eight per cent, of all the radium used in our war 

 equipment. Tiny fractions of luminous paint had to be 

 scraped from gun- and rifle-sights, from compass-cards 

 and aeroplane-indicators. This work alone has saved the 

 country thousands of pounds. 



There is no other place in England, perhaps no other 

 place in the world, which provides a finer example of 

 the triumphs of applied science than our Government 

 Laboratory. While there is, of course, a good deal of 

 routine work, there is no knowing when some new 

 problem may arise. Then the whole burden of responsi- 

 bility falls upon the shoulders of the principal chemist, 



