CAR
CAR
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'tilling coal and other oily substances as chieflyowing to the oil held in solution by the gas.He therefore selected for analysis the gas thatrises in considerable quantity from stagnantwaters during the summer season, which hadbeen before examined by Cruikshank and Dal-ton. This gas always contained 12.5 per cent,of common air, and from 5 to 7 of carbonicacid, which latter being removed, the specificgravity of the remaining gas was 0.011, equalto 0.554 after the removal of the common air,the specific gravity of the latter being 1.000.This gas burns with a large yellow flame, anddetonates when mixed with not less than itsown bulk of oxygen and ignited. On an ave-rage 100 measures of this gas ignited with 205.measures of pure oxygen form 104 of carbonicacid gas. But as carbonic acid contains onlyits own bulk of oxygen, the 104 parts only em-ployed 104 of the 205 of oxygen consumed,ar.d hence the 101 remaining measures went tothe production of water and required 202 mea-sures of hydrogen for that purpose. Reducingthese to the proportions by weight (reckoningcarbonic acid to contain 27.5 per cent, of car-bon) the composition of the pure carburettedhydrogen of this gas from stagnant water wouldgive nearly as follows:
Hydrogen » . 28.
100 .
In fact the sum of the constituent parts thusfound would rather exceed the weight of theoriginal gas, which at any rate would shew that3 io oxygen nor any other ponderable substancecould be present. If this analysis is correct,and it agrees very nearly with that of Dalton,this gas (after extracting the common air andcarbonic acid) is not an oxycarburetted hydro-gen but a simple carburetted hydrogen, and isconsidered by Mr. Dalton as composed of oneatom of carbon and two atoms of hydrogen.
Olefiant gas is the next definite compoundexamined by Dr. T. It was obtained in theusual manner by mixing one measure of alcoholwith three of sulphuric acid, and boiling themixture almost to dryness in a small retort,and collecting the gasseous product over water.This consisted of olefiant gas mixed with car-bonic acid, which last increased in proportionas the process was continued.
This olefiant gas deprived of carbonic acidbut retaining 16 per cent, of common air, was
c An. Chi;
found to have the specific gravity of 0.978(5,hence, by calculation, pure olefiant gas wouldgive 0.9745 sp. gr. (common air being 1.000.)
Olefiant gas when mixed with thrice its bulkof oxygen and ignited, detonates with extremeviolence and produces twice its bulk of car-bonic acid, according to Mr. Dalton, whichvery nearly coincides with Dr. Thomson’s ex-periments. A hundred cubic inches of it (at60° therm, and 50. bar.) weighed 29.72 grains.The weight of its constituent parts (consideredmerely as carbon and hydrogen) as found byanalysis, somewhat exceeded the gas employed,a proof that it could contain no oxygen.
In average numbers it may be considered ascontaining
Hydrogen . . 15.
100 .
Mr. Dalton considers it as containing an atomof carbon and an atom of hydrogen.
Olefiant gas derives its name from its form-ing a singular oily-looking liquid when mixedwith oxymuriatic gas, as already described(Chem. Diet. vol. I. p. 257.) Dr. Thomsonhas further examined this curious substance.A large bottle was filled with olefiant gas and acurrent of oxymuriatic gas being passed into it,the oily substance soon collected at the bottom.Its colour was greenish-white. When drop-ped into water it fell to the bottom, but gra-dually dissolved in it by agitation, and gave thewater a sweet and cooling taste, and a slightaromatic odour. It dissolved completely in al-cohol and sulphuric ether, but not in oil ofturpentine. When left in an open vessel itevaporated, leaving’ only a greenish trace. Itappears therefore to-be totally distinct from theoils.
Olefiant gas is also obtained as a small p3rtof the compound inflammable gas from coal,from caoutchouc, from mineral tar and othercombustible bodies. It is separable fromcommon carburetted hydrogen by oxymuriaticgas as will be further noticed.
Olefiant gas has been more lately analyzedby Th. de Saussure. c To. diminish the extremeviolence of the detonation where this gas isignited with about thrice its volume of oxygen(the quantity that saturates it) the author em-ployed a much larger proportion of oxygen.The general results were the following: 100.parts, in volume, of olefiant gas,.were detonatedi, tom. 78,