3IO THE ALUMNI JOURNAL. 



which are moved by pumping machinery, duce muriatic acid from this magnesium 



As compared to older processes it also chloride by a process patented by Clemm 



has the great advantage that it requires in 1863, viz.; by evaporating the solu- 



very little time for completing the cycle tion, heating the residue in the presence 



of operations, so that large quantities of of steam, and condensing the acid vapors 



chlorine can be produced by a very sim- given off. 



pie and inexpensive plant. These ad- Strange to say, this same method had 



vantages secured for this process the been patented by Mr. Ernest Solvay 



quite unprecedented success that within within twenty- four hours before Mr. 



a few years it was adopted, with a few Weldon lodged his specification. It has 



isolated exceptions, by every large man- been frequently tried with many modi- 



ufacturer of chlorine in the world: yet it fications, but has never been found 



possessed a distinct drawback, viz.: that practicable. Soon afterwards Mr. Wel- 



it produced considerably less chlorine don, with the object of reducing the 



from a given quantity of muriatic acid muriatic acid required by his first 



than either native manganese of good process, proposed to replace the lime 



quality of Mr. Dunlop's recovered man- in this process by magnesia, and so 



ganese. At that time, however, muri- to produce a manganite of magnesia, 



atic acid was produced as a bye-product After treating this with muriatic acid, 



of the Le Blanc process so largely in ex- and liberating chlorine, he proceeded to 



cess of what could be utilized that it was evaporate the residual liquors to dryness, 



generally looked upon as a waste pro- during which operation all the chlorine 



duct of no value. Mr. Weldon himself they contain would be disengaged as hy- 



was one of the very few who foresaw that drochloric acid and collected in con- 



this state of things could not always con- densers, while the dry residue, after 



tinue. The ammonia soda process was being heated to dull redness in the pres- 



casting its shadow before it. Patented ence of air, would be reconverted into 



in 1838 by Messrs. Dvar and Hemming manganite of magnesia, 



it was only after the lapse of thirty years This process was made the subject of 



(during which a number of manufactur- long and extensive experiments at the 



ing chemists of the highest standing works of Messrs. Gamble, at St. Helens, 



had in vain endeavored to carry but did not realize Mr. Weldon's expec- 



into practice) that this process was tations. It, however, led to some further 



raised to the rank of a manufacturing interesting developments, to which I 



process through the indomitable perse- shall refer later on. 



verance of Mr. Ernest Solvay, of Brus- deacon's process without man- 



sels, and his clear perception of its prac- ganese. 



tical and theoretical intricacies. A few Those of you who were present at the 



years later, in 1872, Mr. Weldon already last meeting of the British Association 



gave his attention to the problem of ob- in this city will remember that this sec- 



taining the chlorine of the salt used in tion had the advantage of listening to a 



this process in the form of muriatic acid, paper by Mr. Weldon on his chlorine 



He proposed to recover the ammonia process, and also to another highly in- 



from the ammonium chloride obtained in teresting paper by Mr. Henry Deacon, 



this manufacture by magnesia instead of of Widnes, "on a new chlorine process 



lime, thus obtaining magnesium chloride without manganese." And those of you 



instead of calcium chloride, and to pro- who came with the then President of the 



