524 



ILLUMINATION-. 



far they severally succeed in meeting the actual 

 requirements of the case. 



Gas from Petroleum Alone. Messrs. L. Da- 

 vis & F. M. Parks patented, in 1862, a process 

 for producing a permanent gas for general illu- 

 mination, from petroleum at a very high tem- 

 perature. They employ the crude petroleum, 

 passing this through a double vertical retort, 

 so that the oil may be subjected to a very high 

 temperature at two rapidly succeeding inter- 

 vals. The gas is permanent, but the account 

 does not state what percentage of the petro- 

 leum is in this way convertible into gas, what 

 amount of waste remains from the process, nor 

 what is the exact chemical nature and illumi- 

 nating power, and hence the actual cost and 

 value of the gas obtained. Since the crude pe- 

 troleum contains much water, if some material 

 which will abstract the oxygen of the water be 

 present in the retorts during the process, the 

 liberated hydrogen must act to insure a large 

 increase in the volume of combustible gases, 

 although incombustible carbonic acid must 

 probably, in that case, be mixed with them. 



Hill's Air Gas, Oleo- Water Gas, and Electro- 

 Chemical Gas. Mr. Hill, of New York, secured, 

 June 15, 1858, a patent for an air gas. The 

 process consists in blowing air, oxygen, car- 

 buretted hydrogen, or hydrogen, over, into, or 

 through an oil, such as petroleum, coal oil, 

 naphtha, oil of turpentine, or even alcohol, and 

 igniting the mixture at the orifice of a pipe or 

 burner, a brilliant light being thus produced. 

 By further diluting the oil vapors, by means of 

 increasing the proportion of the gas blown into 

 the oil, a more complete combustion re- 

 sults, with the production of little light, but of 

 an intense heat, said almost to equal that of 

 the compound blowpipe of Dr. Hare. The air 

 gas in this form of combustion is stated to have 

 been already applied as the fuel for driving 

 steam engines, and the inventor is now adapting 

 it to locomotives. By burning the diluted gas 

 within a perforated platinum capsule, an ex- 

 tremely brilliant light is produced, and the pla- 

 tinum cup may be made of any required di- 

 mensions. 



Mr. Hill's oleo-water gas was patented in 1861. 

 In preparing this, a common gas retort is used, 

 billets of pine wood being placed within an 

 iron cage inside the retort ; heat being applied, 

 wood gas distils over (passing on its way 

 through a washer, or purifier), until the wood 

 is converted into charcoal. When the retort 

 hasattained a cherry-red heat, regulated streams 

 of petroleum, or other gas-yielding oil, and of 

 water, are allowed to flow into it. The heat 

 suffices to convert the water'into steam and the 

 oil into vapor, as introduced. The steam parts 

 with its oxygen to the red-hot charcoal (or. in 

 part, it may be, to superfluous carbon in the 

 oil vapor), and a considerable volume of a per- 

 manent illuminating gas passes over into the 

 gasometer, the presumption being that the oil 

 vapor has been destructively changed, combin- 

 ing at the same time with the hydrogen libe- 



rated in decomposition of the steam (water), 

 and that the resulting gas which, to the eye^ 

 burns with a white, clear, and brilliant flame 

 is rich in, or mainly composed of, the highly 

 illuminating bicarburetted hydrogen or olefiant 

 gas. It does not appear, however, that the gas 

 produced has been chemically analyzed, the 

 consumption and illuminating power exactly 

 measured, nor, of course, the comparative cost 

 and value determined. It must be added that 

 the entire body of oxygen abstracted from the 

 admitted water probably goes at the tempera- 

 ture of the retort to the production of its equi- 

 valent of carbonic acid, this product, if really 

 the result, constituting so much incombustible 

 or dead matter already in the gas, as prepared 

 for consumption. A recent statement furnished 

 by Mr. Charles Sears, chemist, gives the best 

 proportions of the materials, for a good strong 

 light, as, of paraflme oil (or other equivalent), 

 one volume ; of water, four volumes ; the pro- 

 duct, when heavy oil is used, being about 1,000 

 cubic feet of gas for two gallons of oil and 

 eight gallons water. . With a retort of 14 x 12 

 inches, the product was about 200 cubic feet of 

 gas per hour. When the residuum of oil dis- 

 tillates is used, the cost of material becomes 

 merely nominal. It is also claimed that the 

 cost of this gas, as produced from petroleum, 

 needs not exceed forty cents per thousand 

 cubic feet. 



The electro-chemical gas is apparently only 

 hydrogen gas set free from water, in the acid 

 liquid of a battery of some thousand pairs, 

 consisting of coils of copper wire and scrap 

 iron successively connected in the manner re- 

 quired, and the whole placed within a vessel 

 called a generator, the liberated hydrogen being 

 subsequently passed through petroleum to be 

 carburetted. The sulphate of iron resulting in 

 the cells of the battery is said to pay the cost 

 of the iron and acid employed. 



McDougaWs Fixed Gas, and Atmospheric 

 Gas. These gases, processes for which have 

 been patented by Mr. S. T. McDongall, of New 

 York, appear to be nearly or quite identical in 

 principle and mode of preparation, as well as 

 in their composition and employment, respect- 

 ively, with Mr. Hill's " oleo-water " and his 

 " air gas." It is claimed that the illuminating 

 power of a jet in which is consumed one and a 

 half cubic feet of the fixed gas per hour, is 

 equivalent to that of fifteen sperm candles ; and 

 also, that the gas can be produced more cheaply 

 than coal gas, and so as to be much cheaper 

 than burning fluid, coal gas, or candles. Its 

 specific gravity is declared to be about 900 (air 

 1,000), that of the best coal gas being from 350 

 to 470. The atmospheric gas, a mixture of va- 

 por of some hydrocarbon with air, can be burn- 

 ed in places and seasons in which the tempera- 

 ture does not fall below 50 F., and it is said 

 to afford a good and cheap light. 



Elmer's Pure Illuminating Gas. Dr. Win. 

 Elmer, of New York, patented, in 1862, a pro- 

 cess in which he claims that from hydrocarbons 



