Annual Report of the Council. Iv 



supplied the basis of their colours. Numerous and mysterious 

 were the names under which tin mordants were sold, " oxy- 

 muriate," " sulphomuriate," " purple spirits," " blue spirits," 

 " scarlet spirits," " double muriate," and so on, there being in 

 many cases a good deal more difference in the name than in the 

 chemical composition of the substance. 



About this time, in connection with this subject, he carried 

 out important technical improvements in the manufacture of 

 stannate of soda. 



From this time forward Peter Hart was constantly engaged 

 in original work of one kind or another, either in elaborating 

 and improving the processes of manufacture carried on in the 

 chemical works of Messrs. Tennants and elsewhere, or in 

 improving or originating methods of analysis. 



It is characteristic of him that, although his original papers 

 are fairly numerous, yet the amount of work which he did in 

 following out his ideas was very great indeed compared with the 

 length of his communications. His results were presented com- 

 plete and fully digested, a paper of a few pages representing 

 generally months of work and perhaps the study of a year or two. 



His genius was essentially practical and simple. Unnecessary 

 elaboration was a bete noir to him. Unless he had satisfied 

 himself beyond all possibility of doubt, and had actually used a 

 new method of analysis continuously, and satisfactorily, he was 

 very diffident about troubling the chemical world with it. 



His method for the estimation of chromium in chrome ore is 

 given by Fresenius in the fourth edition of his Qua?ititative 

 Analysis. It consists in successive fusion with borax, carbonate 

 of sodium, and nitrate of potassium, and was subsequently 

 modified by Dittmar. 



In i860, when the noted Dictionary of Applied Chemistry 

 was published, he, at the request of Sheridan Muspratt, wrote 

 the article on "Sulphuric Acid Manufacture," a sufficient 

 testimony to the fact that he was recognized as one of the leading 

 technologists in his own subjects. In connection with the 

 manufacture of sulphuric acid, in 1865 he devised an apparatus 



