PRESIDENT'S ADDRESS. Ixxix. 



lengthy that as yet little is known. In one of these experiments it 

 required no less than 15 tons of pitch-blende to produce three 

 milligrams of radio-tellurium. Two experimenters have found 

 that uranium, when freed from all trace of radium, would after a 

 time contain a minute quantity, from which fact, and from other 

 considerations, it is supposed that the uranium may be gradually 

 turning into radium. The latter being of such an unstable 

 nature that, according to calculations, only one-millionth part 

 would remain at the end of 26,000 years, requires some means 

 of replenishment. The actual existence of the subtle N-rays, 

 discovered by M. Blondlot, is still questioned by many scientists, 

 but experiments have been made which seem to show strong 

 evidence that they are real and not imaginary. 



The possibility of obtaining the nitrogen of the air by means 

 of electricity, in such a form that it could be used as a fertilser, 

 like the nitrate of soda exported from Chili, was demonstrated 

 so far back as 1781 by Cavendish, but it is only recently that it 

 has been produced as a commercial product by passing air 

 through an electrical furnace, the power being derived from 

 waterfalls in Norway. This will probably have considerable 

 influence upon the wheat supply of the future, when the Chili 

 beds are worked out in 50 years or less. 



A most interesting lecture on diamonds was given by Sir 

 William Crookes to the British Association at Kimberley, which 

 he commenced with the ominous words to those who possess 

 these costly gems, "I am justified in saying that, if the diamond 

 problem is not actually solved, there is every probability that it 

 shortly will be solved." Up to the present time, however, no 

 diamond has been made of more than a millimetre in diameter, 

 and most are microscopic. They have also a great tendency to 

 fly to pieces, so that, on the whole, the danger of competition is 

 not, so far, of importance. Two new methods have recently 

 been discovered: one by the explosion of cordite in a shell, 

 which produces enormous pressure and temperature ; the other by 

 the milder means of heating to a low red heat an alloy of lead 

 and calcium, holding carbon in solution ; but these methods also 



