16 PRESIDENT'S ADDRESS. 



subject I may echo the remarks of the President of the 

 Chemical Section of the British Association and say that we 

 must either have a new definition of an element or exclude 

 radium, uranium, polonium, and various other substances 

 from the list of elements, for if a substance gives off an 

 emanation, or divides into two other substances, how can it 

 come under the well known definition of the term " element," 

 which is not capable of such division ? It has lately been 

 found that potassium emits a radiation, though in a much less 

 degree than radium. Native Tantalum has been met with 

 for the first time in gold washings in the Ural mountains, 

 though in very minute quantities. It is found that aluminium 

 is unsuitable for shipbuilding as it becomes corroded in sea 

 water. Another discovery of a different nature is that when 

 certain dry soils are wetted, heat is evolved, which may 

 perhaps have some influence on the growth of plants. A 

 very delicate test for the presence of blood is a solution of 

 benzidine in acetic acid, which, when brought in contact with 

 blood, becomes of a brilliant blue colour. After many attempts 

 it is at last probable that the chemical nature of the red colour- 

 ing matter of the blood and the green colouring of plants, 

 chlorophyll, will be discovered, the latter being a salt of mag- 

 nesium. I think that after the President's Address to the 

 Royal Society last November I need no excuse for giving you 

 what is no doubt a fragmentary and incomplete account, 

 though I hope correct as far as it goes, of chemical progress. 

 He alludes to the difficulty of understanding the researches in 

 that branch by non-specialists, and asks if it would not be 

 practicable for some of their distinguished chemists to give, in 

 language intelligible to scientific men generally, an outline 

 of the progress of that branch of science. 



ENGINEERING. 



The formation of a Government Department for Aerial 

 Investigation marks a step in the development of this new 

 method of transport which is either already, or is about to 



