430 Mr. W. Herapalli's Experiments on Oil and Coal Gas. 



injured, except iron and copper ; and the substance in the in- 

 terior of cojjper tubes I have by analysis found to be sul- 

 phuret of copper and ammonia; and as ammonia acts upon 

 copper more than any other metal, and copper in this in- 

 stance is more acted on, I think that we may fairly attribute 

 a principal part of the corrosion to the presence of that gas. 

 As a preventative, the ammonia might be removed by adduig 

 to the present mode of purifying a vessel containing dilute 

 acid, or by coating the interior of copper services with some 

 resinous substance; but the best way would be to give up 

 cop}ier altogether, and make use of iron, block-tin, or lead. 



2d, Smell, if allowed to escape without combustion. It will 

 be seen from the experiment, page 426, that they are equally 

 offensive to some palates at least : from mv' own experience I 

 can sav, they are both so much so that I think no person 

 would be induced to smell to either from pleasure. 



3d, Inconveniences resulting from the combustion of the 

 gas. These are, water, lamp-black, and sulphurous acid gas. 

 The first they both form to a very large amount. Dr. Henry 

 gives the com])osition of the gases as follows : 



Oil gas, sp. gr. 906. Coal gas, sp. gr. 500. 



38 olefiant 7 



46*5 carburetted hydrogen 55-8 



3-1 hydrogen 21-3 



9*3 carbonic oxide 11"1 



3-1 azote 4-6 



100 99-8 



In the following calculation I shall consider that a No. 4 

 burner of oil gas consumes two feet per hour, and of coal gas 

 five feet; and that up.on an avei'agc the hours of burning are 

 three and a half per night through the year: in one night a 

 burner of coal gas w^ould consume as much of the three first 

 as contains 944 grs. hydrogen, capable of foi-ming 8496 grs. 

 of water, or 19 oz. 183 grs.; and an oil gas burner equal to 

 this would consume as much of the three first as would con- 

 tain 440 grs. hydrogen, capable of forming 396 grs., or 

 9 oz. 33 grs. of water. 



The lamp-black or carbon which is found attached to arti- 

 cles near where gas is burnt, has been considered by some to 

 be a fault of the gas, whereas it is that which constitutes its 

 perfection; for the only combustible elements of the gases are 

 carbon and hydrogen, and as piu'e In'drogen gives no hght, 

 the whole of it must come from the carbon. When more gas 

 is passed through a burner than oxygen is furnished for, the 



combustion 



