ADDRESS. lxxi 



cially in the organic department of the science. For several years past pro- 

 cesses of substitution (or displacement of one element or organic group by 

 another element or group more or less analogous) have been the main agents 

 employed in investigation, and the results to which they have led have been 

 truly wonderful ; enabling the chemist to group together separate compounds 

 of comparatively simple constitution into others much more complex, and 

 thus to imitate, up to a certain point, the phenomena which take place within 

 the growing plant or animal. It is not indeed to be anticipated that the 

 chemist should ever be able to produce by the operations of the laboratory 

 the arrangement of the elements in the forms of the vegetable cell or the 

 animal fibre; but he may hope to succeed in preparing some of the complex 

 results of secretion or of chemical changes produced within the living 

 organism, — changes, which furnish definite crystallizable compounds, such 

 as the formiates and the acetates, and which he has actually obtained by 

 operations independent of the plant or the animal. 



Hofmann, in pursuing the chemical investigation of the remarkable com- 

 pound which he has termed Triethylphosphine, has obtained some very 

 singular compound ammonias. Triethylphosphine is a body which takes fire 

 spontaneously when its vapour is mixed with oxygen, at a temperature a little 

 above that of the body. It may be regarded as ammonia in which an atom 

 of phosphorus has taken the place of nitrogen, and in which the place of each 

 of the three atoms of hydrogen in ammonia is supplied by ethyl, the peculiar 

 hydrocarbon of ordinary alcohol. From this singular base Hofmann has 

 succeeded in procuring other coupled bases, which though they do not cor- 

 respond to any of the natural alkalies of the vegetable kingdom, such as 

 morphia, quinia, or strychnia, yet throw some light upon the mode in which 

 complex bodies more or less resembling them have been formed. 



The power which nitrogen possesses of forming a connecting link between 

 the groups of substances of comparatively simple constitution, has been 

 remarkably exemplified by the discovery of a new class of amide acids by 

 Griess, in which he has pointed out a new method, which admits of very 

 general application, of producing complex bodies related to the group of 

 acids, in some measure analogous to the Poly-ammonias of Hofmann. 



Turning to the practical applications of Chemistry, we may refer to the 

 beautiful dyes now extracted from aniline, an organic base formerly obtained 

 as a chemical curiosity from the products of the distillation of coal-tar, but 

 now manufactured by the hundred- weight in consequence of the extensive 

 demand for the beautiful colours known as Mauve, Magenta, and Solferino, 

 which are prepared by the action of oxidizing agents, such as bichromate of 

 potash, corrosive sublimate, and iodide of mercury upon aniline. 



Nor has the Inorganic department of Chemistry been deprived of its due 

 share of important advances. Schbnbein has continued his investigations 

 upon ozone, and has added many new facts to our knowledge of this 

 interesting substance; and Andrews and Tait, by their elaborate investigations, 



