202 
ON THE WELDON PROCESS FOR THE MANUFACTURE 
OF CHLORINE. 
{A Paper read before the British Association.) 
Mr. W. Weldon, F.C.S., the author, said the process was 
one for the manufacture of chlorine by means of a perpetually 
regenerated reagent, consisting mainly of a compound con- 
taining the elements of peroxide of manganese and lime, and 
which was previously unknown. He had described the 
process last year at the Exeter meeting, when it was in 
operation at only two works. It is now either in operation or 
on the point of being adopted at almost all the works in this 
country, and at a number of works in France and Germany. 
In consideration of the fact that the production of chlorine 
will probably be completely revolutionised by the Weldon 
process, and considering, likewise, that chlorine is largely 
prepared in the neighbourhood of Liverpool and in other parts 
of Lancashire, the author has agreed to the request of Prof. 
Roscoe, that he should submit to the section a brief account 
of the practical results which the process has been found to 
yield under more extended experience, and of the develop- 
ment which it had undergone during the year. The author 
first described the apparatus employed, and exhibited a small 
model of it; and then proceeded to state that the chloride of 
manganese, which results in the ordinary preparation of 
chlorine, and which is generally acid, is neutralised by adding 
to the liquor finely divided carbonate of lime. The liquor 
then consists of a neutral mixed solution of chloride of man- 
ganese and chloride of calcium, and contains, in suspension, a 
large quantity of sulphate of lime and smaller quantities of 
oxide of iron and alumina. The clear solution, after settling, 
is oxidised by passing into it a blast of atmospheric air from a 
blowing engine, and heated, if necessary, by a current stream. 
Milk of lime is then run into the oxidiser until the liquid 
ceases to give a manganese reaction with solution of bleaching 
powder. A further quantity of milk of lime is added, and 
ultimately from eighty to eighty-five per cent, of the man- 
ganese is converted into peroxide. The mixture is allowed to 
settle, the chloride of calcium solution forming the super- 
natant liquid is run off, and the residual black mud containing 
the manganese peroxide is used in the stills where hydro- 
chloric acid is decomposed and chlorine gas produced. A 
residual liquor such as was commenced with results, and the 
round of operations is begun again ; and bo on, time after 
