74.0 REPORT—1896. 
it to the required temperature, and thence through a mass of broken bricks im- 
pregnated with sulphate or chloride of copper contained in a chamber or cylinder 
called a decomposer, which was protected from loss of heat by being placed in a 
brick furnace kept sufficiently hot. In this apparatus from 50 to 60 per cent. of 
the hydrochloric acid in the mixture of gases was burnt to steam and chlorine. In 
order to separate this chlorine from the steam and the remaining hydrochloric 
acid the gases were washed with water, and subsequently with sulphuric acid. 
The mixture now consisted of nitrogen and oxygen, containing about 10-per cent. 
of chlorine gas, which could be utilised without any difficulty in the manufacture 
of bleach liquors and chlorate of potash, and which Mr. Deacon also succeeded 
in using for the manufacture of bleaching powder, by bringing it into contact 
in specially constructed chambers with large surfaces of hydrate of lime. 
Within recent years this latter object has been attained in a more expeditious and 
perfect manner by continuous mechanical apparatus (of which those constructed 
by Mr. Robert Hasenclever and Dr. Carl Langer have been the most successful), 
in which the hydrate of lime is transported in a continuous stream by single or 
double conveyors in an opposite direction to the current of dilute chlorine, and the 
bleaching powder formed delivered direct into casks, thereby avoiding the intensely 
disagreeable work of packing this offensive substance by hand. 
Mr. Deacon's beautiful and scientific process thus involves still less movement 
of materials than the very simple process of Mr. Weldon, because in lieu of large 
volumes of liquids he only moves a current of gas through his apparatus, which 
requires a minimum of energy. The only raw material used for converting hydro- 
chloric acid into chlorine is atmospheric air, the cheapest of all at our command. 
The hydrochloric acid which has not been converted into chlorine by the process is 
all obtained, dissolved in water, as muriatic acid, and is not lost, as in previous 
processes, but is still available to be converted into chlorine by other methods, or 
to be used for other purposes. 
In spite of these distinct advantages, this process took a long time before 
it became adopted as widely as it undoubtedly deserved. This was mainly due to 
the fact that the economy in the use of muriatic acid which it effected was at 
the time when the process was brought out, and for many years afterwards, no 
object to the majority of chlorine manufacturers, who were still producing more 
of this commodity than they could use. Moreover, there were other reasons, The 
plant required for this process, although so simple in principle, is very bulky 
in proportion to the quantity of chlorine produced, and, as I have pointed out, the 
process only succeeded in converting about one-third of the hydrochloric acid 
produced into chlorine, the remainder being obtained as muriatic acid, which had in 
most instances to be converted into chlorine by the Weldon process; so that the 
Deacon process did not constitute an entirely self-contained method for this 
manufacture. This defect, of small moment as long as muriatic acid was produced 
in excessive quantities, was only remedied by an invention of Mr. Robert 
Hasenclever a short number of years ago; when by the rapid development of the 
ammonia soda process the previously existing state of things had been completely 
changed, and when, at least on the Continent, muriatic acid was no longer an 
abundant and valueless by-product, but, on the contrary, the alkali produced 
by the Le Blane process had become a by-product of the manufacture of cblorine. 
Mr. Hasenclever, in order to make the whole of the muriatic acid he produces avail- 
able for conversion into chlorine by the Deacon process, introduces the liquid 
wuriatic acid in a continuous stream into hot sulphuric acid contained in a series 
of stone vessels, through which he passes a current of air. He thus obtains 
a mixture of hydrochloric acid and air, well adapted for the Deacon process, 
the water of the muriatic acid remaining with the sulphuric acid, from which it 
is subsequently eliminated by evaporation. In this way the chlorine in the 
hydrochloric acid can be almost entirely obtained in its free state by the simplest 
imaginable means, and with the intervention of no other chemical agent than 
atmospheric air. Since their introduction the Deacon process has supplanted the 
Weldon process in nearly all the largest chlorine works in France and Germany, 
and is now also making very rapid progress in this country. 
