PRESIDENT’S ADDRESS—SECTION B. 59 
significance, and modern organic chemistry confines itself to the 
hydro-carbons and their derivatives. Among the more striking 
synthetical processes are Berthelot’s preparation of acetylene by 
the direct combination of carbon and hydrogen, and Kolbe’s 
preparation of acetic acid (1845) from carbon disulphide in 
several stages. Since then the synthetic production of organic 
substances has progressed in a highly remarkable way. From 
these comparatively simple compounds we are now able to pre- 
pare the most complex organic compounds, containing a large 
number of carbon atoms linked together. 
Of the more complex organic acids, tartaric acid was the first 
to be synthetically prepared by a series of reactions, the final 
one of which was provided in 1861 by Maxwell Simpson by the 
formation of succinic acid from ethylene through ethylene 
cyanide. This reaction enabled chemists to prepare acids con- 
taining one or more carbon atoms more than the original hydro- 
carbon. 
Outside the domain of philosophical chemistry the art of the 
preparation of organic compounds by synthesis has been made 
use of in the preparation of innumerable compounds used com- 
mercially. It will be sufficient to enumerate a few of these. 
The preparation artificially of alizarin from anthracene by 
Graebe and Liebermann, and by Perkin. This substance had 
been exclusively prepared from the madder for thousands of 
years, and its artificial production replaced a staple trade 
of Turkey, Holland, France, and Italy. Indigo, another dye 
stuff, has been artificially prepared by Baeyer. Of substances 
used for dyeing, and prepared synthetically, the most important 
are undoubtedly the well-known aniline dyes, aniline being a 
derivative of coal-tar. The practical application of the aniline 
compounds to the dyeing industry is due to W. H. Perkin. The 
use of these dyes has completely revolutionised the dyeing in- 
dustry. On this account the discovery of the aniline dyes must 
be mentioned here, though it is not an instance of a naturally 
occurring vegetable or animal substance prepared synthetically. 
Of other synthetic preparations of complex compounds may be 
mentioned. salicylic acid, coumarin (Perkin), vanillin, one or 
two alkaloids, such as conine (Ladenburg), cocaine, &c. 
Emil Fischer has prepared some of the sugars by synthesis 
from glycerine. 
THE DISCOVERY OF NEW ELEMENTS. 
The elements known to Lavoisier, and at the beginning of the 
century, were few in number, and a history of the discovery of 
_ new ones, or the proof of the compound nature of substances 
previously considered to be elements, would delay us too long. 
As landmarks in the progress in this department of chemical 
