TRANSACTIONS OF SECTION B. 739 
later, in 1872, Mr. Weldon already gave his attention to the problem of obtaining 
the chlorine of the salt used in this process in the form of muriatic acid. He pro- 
posed to recover the ammonia from the ammonium chloride obtained in this 
manufacture by magnesia instead of lime, thus obtaining magnesium chloride 
instead of calcium chloride, and to produce muriatic acid from this magnesium 
chloride by a process patented by Clemm in 1863, viz., by evaporating the solution, 
aed residue in the presence of steam, and condensing the acid vapours 
iven off, 
‘ Strange to say, this same method had been patented by Mr. Ernest Solvay 
within twenty-four hours before Mr. Weldon lodged his specification. It has 
been frequently tried with many modifications, but has never been found practic- 
able. Soon afterwards Mr. Weldon, with the object of reducing the muriatic acid 
required by his first process, proposed to replace the lime in this process by mag- 
nesia, and so to produce a manganite of magnesia. After treating this with 
muriatic acid and liberating chlorine he proceeded to evaporate the residual 
liquors to dryness, during which operation all the chlorine they contain would be 
disengaged as hydrochloric acid and collected in condensers, while the dry residue, 
after being heated to dull redness in the presence of air, would be reconverted 
into manganite of magnesia. 
This process was made the subject of long and extensive experiments at the 
works of Messrs. Gamble at St. Helens, but did not realise Mr. Weldon’s expecta- 
tions. It, however, led to some further interesting deyelopments, to which I shall 
refer later on. 
Those of you who were present at the last meeting of the British Association 
in this city will remember that this Section had the advantage of listening to a 
paper by Mr. Weldon on his chlorine process, and also to another highly interest- 
ing paper by Mr. Henry Deacon of Widnes ‘on a new chlorine process without 
manganese,’ And those of you who came with the then President of the Section 
(Professor Roscoe) to Widnes to visit the works of Messrs. Gaskell, Deacon, and Co. 
will well remember that at these works they saw side by side Weldon’s process 
and Deacon’s process in operation, and no one present will have forgotten the 
thoughtful, flashing eyes and impressive face of Mr. Deacon when he explained to 
his visitors the theoretical views he had formed as regards his process. 
Mr. Deacon had made a careful study of thermo-chemistry, which had been 
greatly developed during the preceding decade by the painstaking, accurate, and 
comprehensive experiments of Julius Thomsen and of Berthelot, and had led the 
latter to generalisations which, although not fully accepted by scientific men, 
have been of immense service to manufacturing chemistry. 
Mr. Deacon came to the conclusion that, if a mixture of hydrochloric acid with 
atmospheric air was heated in the presence of a suitable substance capable of 
initiating the interaction of these two gases by its affinity to both, it would to a 
very great extent be converted into chlorine with the simultaneous formation of 
steam, because the formation of steam from oxygen and hydrogen gives rise to the 
evolution of a considerably larger quantity of heat than the combination of 
hydrogen and chlorine. Mr. Deacon found that the salts of copper were a very 
suitable substance for this purpose, and took out a patent for this process in 1868. 
He entrusted the study of the theoretical and practical problems connected with 
this process to Dr, Ferdinand Hurter, who carried them out in a manner which 
will always remain memorable, and will never be surpassed, as an example of the 
application of scientific methods to manufacturing problems, and which soon 
placed this beautiful and simple process on a sound basis as a manufacturing 
operation. 
In the ordinary course of manufacture the major part—about two-thirds—of 
the hydrochloric acid is obtained mixed with air and a certain amount of steam, but 
otherwise very little contaminated. Instead of condensing the muriatic acid from 
this mixture of gases by bringing it into contact with water, Mr. Deacon passed it 
through a long series of cooling pipes to condense the steam, which of course 
absorbed hydrochioric acid, and formed a certain quantity of strong muriatic 
acid, The mixture of gases was then passed through an iron superheater to raise 
