124 



UNDULATOUY FORCES. LIGHT. 



[WATER-OAS. 



Radley, Lowe, White, ('roll, \V,l,v., , and 



. in i.r.H.f of the uuinluT of persons win. !, 

 out patents in this country fur I ; and 



naphtlialiaatiou of water-gas. In t>vi-ry r.t-- t ':. 

 rather thu steam, is decomposed by passing it 

 hot coke or charcoal ; and it is >ul.^'i|Urir.U naphtlialued 

 by passing it over rich hydro-cut 



The details of tho process vary with the nature of the 

 materials used. \Vln-n fat :in<l resin are employed, tho 

 prooen, as descii!.. I by Mr. White in his patent, is as 

 follows: Two retorts, about seven feet long ami nine 

 inches in diameter, are set vertically in a furnace so that 

 they may i 1:. ated to full redness, or even to an 

 incipient white heat. A flue passes through tho centre 

 of each of the retorts, in order that th'e contents may be 

 thoroughly heated. They are packed full of coke, 

 charcoal, or anthracite, and a few scraps of iron. When 

 the retorts are red-hot, water is allowed to flow through 

 a syphon upon the top of the ignited mass. The steam 

 which is thus generated, passes over the red-hot coke, 

 and is decomposed into hydrogen and carbonic oxide, 

 which is incidentally attended with more or ]< 

 carbonic acid. Tho gases and vapours thus prod:; 

 escape from the bottom of the retorts into two others 

 placed horizontally in the same furnace. These are 

 about six feet long, and are divided into two or mon; 

 compartments by longitudinal divisions which reach 

 nearly to the end. The compartments are filled with 

 coke, chains, or coils of iron wire, so as to increase the 

 surface ; and into the first of these, tar, fat, or resin is 

 allowed to flow, so as to undergo decomposition. The 

 evolved gases are rapidly carried off and mixed with the 

 gaseous products of the first retort ; and after they have 

 passed through a condenser ami a lime purifier, they 

 go on to the gasometer. In working the process, the 

 supply of the materials should be so managed, that the 

 us mixture should consist of about four parts of 

 water to six of the material. When resin is used, the 

 proportions of the various materials are, one hundred- 

 weight of resin, seven-ond-a-quarter gallons of resin-oil, 

 fifteen pints of water, a sixth of a bushel of charcoal, and 

 a few ounces of scrap iron. These produce from 1 ,500 to 

 1,600 cubic feet of gas, and about three gallons of oil. 

 Dr. Frankland has entered iato a very detailed exami- 

 i of this process; and it appears from his report, 

 that a hundredweight of resin, with from thirty to forty 

 pints of water, will yield from 1,500 to 1,900 cubic feet of 

 gas, and f n >m two to four gallons of oil. The temperature 

 at which tho best results are obtained is that of dull 

 redness ; for if the heat be carried much above this point, 

 the richer gases are decomposed, and changed into several 

 gases of low illuminating powers. He found that two 

 distinct changes were effected in the water-retorts. In 

 one case tho steam was decomposed by the red-hot 

 charcoal, and equal volumes of hydrogen and carbonic 

 were indirectly produced ; in tho other, it was con- 

 verted into two volumes of hydrogen, one of carbonic 

 acid being also evolved. These mixed gases, together 

 with some nude-composed steam, pass into the resin 

 retort, where they mix with the vapours of the decom- 

 posing resin, and pass twice along the length of tho red- 

 hot retort. Hero the steam is again subjected to 

 decomposition by tho agency of the fuliginous matter 

 evolved from the resin. This change is a very important 

 one, for it prevents the accumulation of carbon in the 

 exit-pipe of the retort. If the gas be examined at this 

 stage of its manufacture, it will be found to contain a 

 very large proportion of carbonic acid ; and one of the 

 greatest difficulties in the subsequent management of it, 

 is the removal of this impurity. Ordinary wet lime will 

 only remove a portion; and hence Dr. Frankland h:n 

 reooinni'-udi-d the use of caustic soda, which may be 

 produced by the admixture of carbonate of soda with 



B nt lime. 



The gas which is thus produced has a specific gravity 

 of from <KK) to (UK*. m from seven to eight per 



cent, of condeiisiblu hydro-carbons; and its illuminating 

 power is about the same as tliat of ordinary cannel gas. 

 Itacompoiiition is as follows : 



Ordinary ga. 



hydro-carbons . . 7 II . 

 Light earburetted hvdrogen . 'Ji'raO . 



.gen 4(> 



Carbonic oxide ...... 18-66 . 



Carbonic acid 7'27 . 



Pan | .-. 

 813 



4338 

 1878 



o-oo 



10000 10000 



According to Dr. Frankland's report, hydro-carbon gas, 

 from steam and resin, may be manufactured at from 9|<J. 

 to 1*. IJrf. per 1,000 cubic feet. This is irrespective of 

 the cost of the apparatus, or of tho charge for wear and 

 



\Vhon tho gas is made from rich cannel coal, tho ar- 

 rangement of the apparatus is a little different from tho 

 preceding. In such cases tho patentee adopts tho follow- 

 ing plan : 



Both retorts are placed horizontally, and they are 

 divided into two comportments by means of a longitudinal 

 septum that re; rly to the end of each. Tl 



called the water-retorts, are charged with coke ; and after 

 being raised to a high temperature, water is allowed to 

 fall gently through a syphon-pipe upon the red-hot coke 

 at tho outer end of the upper compartment. The steam 

 which is thus generated passes through the ignited con- 

 tents of the upper compartment, and thence descending 

 behind the septum, it comes forward tljpough the lower. 

 13y these means it is exposed to a large surface of red-hot 

 charcoal, and is in great part decomposed, and hydrogen, 

 carbonic oxide, and a little carbonic acid are produced, 

 all of which enter the lower compartment of another re- 

 tort, wlu'ch is charged with cannel e.oal. line they mix 

 with the various hydro-carbons that are evolved from tho 

 coal ; and after traversing the retort from one end to the 

 other and back again, they pass into the condenser and 

 wet-lime purifier, and thence into the gasometer. Dr. 

 Frankland states, that by this mode of working, all the 

 carbonic acid which is generated in the water-retort is 

 decomposed by the fuliginous matter of the coal, and 

 converted into twice its bulk of carbonic oxide. It is 

 thought, also, that the water-gases exert a conservative 

 influence on the rich hydro-carbons which are evolved 

 from the coal ; and that by sweeping them away as fust 

 as they are produced, and so protecting them from the 

 destructive agency of heat, a much larger quantity of 

 illuminating matter is obtained. 



Dr. Frankland has examined the value of this process, 

 as applied to different varieties of cannel coal. He 

 worked with one hundredweight of each of the following 

 coals, and he obtained the following amounts of mixed 

 hydro-carbon gases. The coals wore placed in each of 

 tile compartments of tho second retort, and they were 

 distilled at a low red-heat. The water-gas was obtained 

 in the usual manner : 



Name of coal. 



Yield per Ion. 



Illuminating power 



of the gas 

 in sperm candid. 



20-0 

 191 

 18-8 

 21-0 

 28-7 

 17-9 



Wigan (Inco Hall) . 16,120 , 



Ditto (Balcarres) .. 15,600 . 



Newcastle cannel . . 15,020 



Methyl 26,400 . 



Lesmahago .... 29,180 . 



Boghead 61,720 . 



The illuminating power was tested in the usual way 

 with a No. 4 fish-tail burner, consuming five cubic feet 

 per hour, at a pressure of half, an inch of water ; and the 

 candle was a sperm candle, calculated to the amount of 

 120 grains per hour. According to Dr. Fyfo's rn<xle of 

 estimating the value of tho gas, on average sample has a 

 durability of 43 minutes ana 20 seconds, and its amount 

 of condensation by chlorine, w;is 11-44 per cent. ; so that 

 its quality was about 2j that of ordinary gas from New- 

 castle coal. 



Mr. Clegg speaks highly of the value of this process. 

 He says that a ton of \Vi'.;an coal yieMs under ordinary 

 circumstances, about 10,000 cubic feet of twciity-candLu 

 ifos ; while with the hjrdrO-OMrboB process it furnishes 

 JG.CXX) cubic foot of gas of tho same quality, and 20,000 

 cubic foet of twelve-candle gas. A ton of Lcsmaluigo 





