1888-89.] II3 



cuit and rings a bell. The tampering with our safes, doors, 

 and windows, and the increase of temperature in our shops and 

 warehouses by fires breaking out, are indicated in a similar way. 

 Telegraphs have been perfected by which portraits of criminals 

 can be accurately transmitted, and when caught, and the 

 extreme sentence of the law passed upon them, the penalty can 

 be carried out by this wonderful power. 



In chemistry, the past twenty-five years has been marked by 

 a similar advance in knowledge. Not only has the system of 

 nomenclature been changed, but the number of distinct elemen- 

 tary bodies has been increased to seventy (not including the 

 twenty, or more, new elements said to have been discovered by 

 Kriiss and Nilsen in certain rare Scandinavian minerals) 

 Spectrum analysis has given to us a knowledge of the chemical 

 constitution of the sun and stars. The investigations which 

 have recently been laid before the Royal Institution by Mr. 

 Crookes, with reference to the examination of bodies under 

 electric discharges in vacuo would point to the possibility of 

 decomposing some of the elementary substances and resolving 

 them into more simple forms, as he states there is reason to 

 suspect that Yttrium has been formed by the combination of 

 six simpler substances, caused by varying states of electricity 

 and heat to shape themselves into that element. Within the 

 last year M. Moissan has succeeded, after three years' incessant 

 labour, in the isolation of Fluorine, a substance which burns 

 hard crystalline Silicon like tinder, sets fire to organic matter, 

 and forms fluorides by incandescence with many other elements. 



The direction in which chemical research has had, perhaps, its 

 greatest development, so far as commercial enterprise is con- 

 cerned, has been in the utilisation of the coal tar products. It 

 was in the year 1856 that Mr. W. H. Perkins, while carry- 

 ing on investigations as to the probability of artificially prepar- 

 ing quinine, discovered the substance from which the colour 

 mauve is produced. Soon after, about the year 1859, came the 

 discovery, by a French chemist, of the brilliant red colour 

 Fuchsine, or Magenta and Solferino, as some of its shades 



