80 CONSTRUCTION OF RETORTS. 



" Another advantage in this retort is, that its being open at each end and the charge 

 having to pass directly through it, there is no deposit of carbonaceous matter, which is 

 an evil in the ordinary retorts which is attended with much inconvenience and destnic- 

 tion, and which has yet in no case been remedied or rather prevented. The patent re- 

 torts, after working twelve months, have been taken down and found quite free from any 

 incrustation. 



" I have now gone through the form and arrangement of the patent retort ; from its 

 simplicity, and the saving of labour, time and tools as no rakes or iron barrows are 

 required, and the fuel must be reduced in proportion to the size of the ovens and the 

 retorts, and the conducting principle of the material for heat it must be obvious that 

 very considerable saving must be realized. 



" I shall now proceed to show what I consider to be the chemical advantages that my 

 retort possesses over the ordinary retort ; that 35 per cent, more gas can be made by it 

 from the same coal and in the same time. In the first instance, it is well known to all 

 who are acquainted with gas-making in the ordinary way, that when coal is introduced 

 into a retort at a bright red heat (the best for the production of gas), the first products 

 that pass up the exit-pipe are moisture, with a volume of small particles of coal ; and the 

 atmospheric air that had gathered in the retort from the interstices between the coal just 

 put in composes the mere undecomposed vapour, which is inflammable for a very consider- 

 able time after the retort is closed ; this vapour, when the coals begin to ignite, forms the 

 constituent parts of the tar and ammonia, the atmospheric air passing into the gas during 

 forty minutes in an ordinary-sized retort. The greatest part of the product is composed 

 principally of tar, rich with naphtha and ammoniacal liquor, that distils over with the gas, 

 and that of a poor quality, the gas being only produced from that part of the coal which 

 touches the red-hot retort, the body of the coal not yet being sufficiently ignited to de- 

 compose the products issuing from their interior ; and it is not until the pieces of coal 

 become charred on the exterior surface that the matter which they are disengaging be- 

 comes a gas fit for illumination. 



" Comparing the above process with that of the patent retort, the advantages cannot 

 but be obvious ; the coals being introduced at one end and the gas and carbonized coke 

 discharged at the other, it is very palpable, that all the particles, of whatever kind, dis- 

 engaged from the newly-introduced coal must pass over the red-hot coke and undergo a 

 more perfect decomposition than it is possible on the ordinary plan, and thus the tar, 

 naphtha and ammoniacal liquor are 50 per cent, less than from the common retort, which 

 I have repeatedly proved by experiment, and am daily confirmed in the truth I have here 

 advanced by the working of not less than fifty retorts in the West Bromwich gas esta- 

 blishment. 



" The rationale on which I ground the above process is as follows ; viz. the naphtha 

 and tar (carbon and hydrogen), the water (oxygen and hydrogen), and the ammonia 

 (hydrogen and nitrogen), are all evidently decomposed to a certain extent. The oxygen 



