1S40.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



309 



A NEW PROCESS FOR MAKING GAS FOR ILLUMINATIONS 

 FROM BITUMINOUS SCHIST. 



The utilization of bituminous schist is a subject of great importance, 

 as promising to make tliis substance profitable. M. Selligue is the 

 inventor of the process for distilling this mineral, and has works for 

 the purpose on a large scale. His mines are in the department of 

 Saone and Loire, between Autun and the Central Canal ; his three 

 works are at St. Leger-du-Bois, Canton of Epinal ; Surmoulin, near 

 Autun, and Igernay, Canton of Cardesse. In these works the schist 

 is distilled in close retorts, they leave a residuum of carbonaceous 

 matter, which may be used for disinfection or discolouration, but not 

 yet made serviceable. The volatile products are oils consisting prin- 

 cipally of dirterent carburets of hydrogen, which are made available 

 for profit. A great quantity of intlammable gases are also disengaged 

 during the distillation, and are directed into the furnace and used as a 

 combustible. 



The schists of Autun are very variable in character, but all are re- 

 jected which afford less than 6 per cent, of oil on distillation, but those 

 now used average 10 per cent., it is not rare however to find as much 

 as 20 or 25 per cent., some were as much as half their weight of 

 oleaginous products. 



The composition of 100 parts of liquid bitumen is as follows: 

 Light oil of variable density from 0-766 to 0.810, 



used for gas .-..-. 35.57 

 Oil of greater density susceptible of being used 



in lamps .-.-•.. 25-85 

 Fattv matter containing 12 per cent, of parajfine 12- 



Pitch or tar 17-28 



Residue 9-3 



100 



It has long been suspected that the defiant gases derive their 

 illuminating properties from the oleaginous vapours which accompany 

 the generally slightly carburetted hydrogen gas which always forms 

 the base of these gases. M. Pelletan maintained this view in a paper 

 read before the Academy in December 1816, and it has been confirmed 

 by M. Selligue. It has been on the other hand asserted and received 

 as certain that oxidated carbonic gas is always injurious in illuminating 

 gas, and that it diminishes the brilliancy of the flame by lowering its 

 temperature, on account of the low degree of heat developed during 

 its combustion. M. Selligue has however established the fallacy of 

 this doctrine. 



M. Selligue's process is as follows : — Three tubes or retorts, situated 

 vertically in a new and ingeniously constructed furnace, are heated 

 red. The first and second contains charcoal, and as fast as the char- 

 coal disappears it is reolaced, which is every five hoars. This carbon 

 is for the purpose of effecting the decomposition of the water intro- 

 duced into the first tube in a continued stream, and where it is con- 

 verted into hydrogen gas, and carbonic acid, and oxide of carbon. But 

 as the production of carbonic acid is to be avoided, the gases produced 

 by the first tube are conducted into the next, where they are exposed 

 again to incandescent charcoal, by which means the carbonic acid 

 first formed is converted into oxide of carbon. The furnace is so ar- 

 ranged that this tube is the hottest of the three, so as to favour the 

 total decomposition of the carbonic acid. 



The third tube is fitted with iron chains, the use of which is to pre- 

 sent a large incandescent metallic surface, capable of distributing 

 caloric in an equal and rapid manner to the gases or vapours passing 

 through. On the one side this tube receives the gases produced by 

 the decomposition of the water in the two preceding tubes, and in the 

 other a continued stream of light schislose oil. This light oil is de- 

 composed into new products still more volatile, and passes with the 

 gas into a refrigerator, which by cooling down the products causes 

 some of them to reappear. The schistose oil is therefore not entirely 

 gasified, but that which does not change into gaseous matter is pre- 

 served uninjured. What is very singular is that the links of the chain 

 in tlie tube are never covered with any carbonaceous deposit. Thus 

 while the schistose oil is evidently decomposed by heat during this 

 operation, its decomposition is modified in a successful manner by its 

 diffusion amid a large volume of gas, such as that produced from the 

 decomposition of water, and whicYi serves as a vehicle. 



From the third tube is produced hydrogen and oxide of carbon, 

 produced from the decomposition of the water, and the gases or va- 

 pours from the decomposition of the oil. By passing into the appara- 

 tus 20 gallons of vi'ater, and 25 of schistose oil, 50,000 gallons of oil fit 

 for illumination are produced in twenty hours. The gas so produced 

 requires no farther purification, having passed through a refrigerator 



where are deposited the nondecomposed oil, and steam from the water. 

 From the refrigerator the gas passes into the gasometer. 



M. Selligue's process and apparatus are represented as being so 

 simple, as to be easily used in factories and private establishments, while 

 the price of the gas so produced is low enough to be employed for 

 lighting the streets. It has been proved by experiment not to de- 

 teriorate, but to improve at a distance from the gasometer; at five 

 miles distance the flame was purer than when just issuing from the 

 gasometer. When cooled down to 13" F. below zero, its illuminating 

 power was not sensibly diminished. The gas is also free from sul- 

 phuretted compounds, and gives no unpleasant smell. The odour of 

 coal gas, we may observe, however, is attributed by some chemists to 

 vapour of naptha, and not to sulphur solely. As it does not act upon 

 metallic reflectors, M. Selligue is able to use these additions with great 

 advantage, so much indeed that with a parabolic reflector one of his 

 burners enables a middling size print to be read 80 yards off. 



M. Selligue has set up gas apparatus at the Royal Printing House, 

 and the BatignoUes at Paris ; at Dijon, and other cities, all of which 

 work well. 



We may observe that this process is on similar principles to that of 

 the air light, in which air was decomposed and the oxygen burned 

 with oily or bituminous matters, and in this case water is decomposed 

 and the hydrogen similarly combined. 



STONE FOR THE NEW HOUSES OF PARLIAMENT. 



Sir — 1 wish your correspondent in No. 33 of your valuable Journal who 

 stiles himself " Amicus," had done that which he started to do in tlie first 

 part of his letter, or at least what he pretended his epistle should do, and 

 have endeavoured to correct the many " inaccuracies and misstatements," 

 which have already appeared, and not have added to their number by writing 

 the letter under notice, which is nothing more or less than a perfect puff, to 

 extol his fortunate purchase of " Mansfield Woodhouse Quarr)-," as well as 

 his other " White Sandstone Quarr)-," as he calls it. 



It is very true and well known that Commissioners were appointed by 

 Government to select the best material the united kingdom could produce, as 

 to durability ; and well they have performed their task, certainly. In the 

 first place they only go two-thirds over the kingdom, leaving out the only 

 part that could yield them the article wanted, such an article as is to be found 

 in most parts of Ireland, for it is well known tliat that country abounds with 

 stone of an nndecaying nature (as for instance look at her " Round Towers,") 

 and selected a material not half so good as that which could have been pro- 

 cured as above, and from a quarry too according to their own showing, that 

 could not produce the necessary quantity or blocks of sufficient magnitude 

 for tlie purpose intended, as witness the Report published by the House of 

 Commons (which any one can purchase for sixpence), there it is stated the 

 depth of workable stone to be only " 12 feet," and the size of the blocks to 

 be no more then from " 8 inches to 2 feet." Now how can such slovenly 

 conduct be tolerated, but this is not all, for as " Amiens " shows, they were 

 within a few months obUged to abandon this mighty quarry and seek a new 

 one, in the newly discovered quarry purchased by Air. Lindley, alias Amicus, 

 which that gentleman states to be of a quality and character precisely similar 

 " to that of the beds on the Jloor," if that is so, and we have no reason to 

 say otherwise, then the stone will he found wanting in the same manner as 

 the Balsover, in not possessing blocks of the size required. So much for 

 " Amicus," having set at rest the " inaccuracies and mis-statements," that 

 have gone abroad. But before I have done, I must ask him a question or 

 two, which no doubt he will be enabled to answer, which will show how the 

 public are generally imposed on in jobs of this nature, lias the New Mansfield 

 Woodhouse Quarr)' been enabled to supply the Works yet, with either quan- 

 tity cr quality as to size of blocks, or will it ever ? If it has, why have the 

 said works been so nearly at a stand still for some time, and why has the 

 Steettey Quarry been apphed to for the required supply, and whether that 

 appUcation has not been answered by the sending of great quantities to West- 

 minster to carr)- on the building .' And lastly, though not the least point of 

 the business, whether this said stone has ever been tested by the Commis- 

 sioners aforesaid .' If so, I can find no report thereof, which ought to have 

 been done, the public having a right to expect that no material should be 

 stealthily used in their national buildings without having it duly tried in all 

 possible ways, particularly after the heavy sum that has been paid these gen- 

 tlemen to protect their interest and fame. 



If these questions are well and truly answered, then indeed will " Amicus"' 

 be correcting the " inaccuracies and mis-statements" that have gone abroad, 

 and be rendering the public infinite service by showing them how they are 

 generally hoodwinked in snch matters. 



I cannot conclude this letter without referring him and your readers to a 

 most excellent article in the same number, " On Limestone in Ireland," by 

 W. Bald, F.R.S.E., &c., a gentleman of the very first rate talent and ability, 

 which I have no doubt has been duly seen and read by all who are fortunate 

 enough to take in your valuable journal, but should it have escaped the eyes 

 of any, I can only say it will well repay their looking back to and reading it 

 mth attention, then all will I am sure hear me out in my censure of the 



2 T 



