24:8 , ANNUAL OF SCIENTIFIC DISCOVERY. 



have lately been brought into use, the results obtained have been of the 

 most satisfactory character. They embrace the best parts of the improve- 

 ments made abroad and at home, and will tend to obviate the evil every 

 where felt, of a high natural temperature not under control in the conden- 

 sation of gas. 



5th. " Are there any suggestions which should be made to consumers 

 upon the proper and eeonomical use of gas ? " 



It has long been the custom in London to issue to consumers of gas, 

 from time to time, little tracts on the subjects of gas distribution, measure- 

 ment, and care of fixtures ; this last is of eminent importance. A compi- 

 lation of this kind has been examined by myself, and it will probably soon 

 be published here. As the duty of the manufacturer of gas to the con- 

 sumer ceases when he has delivered within the meter a pure gas of high 

 illuminating quality, under a regulated pressure, attention is required of 

 the consumer, if he would enjoy the comfort and advantage of a good light. 

 Illuminating gas is not a permanent body, and it cannot, like air, enter and 

 leave small tubes without soiling them, especially if it reposes in them 

 when air has access. It has a constant tendency to produce fluid, and even 

 solid bitumens, by oxidation from admixture with air ; and in the open 

 space between the key and the stop-cock and the burner, except while 

 the gas is burning, air is always present. 



Hence all fixtures require periodical cleaning, as every species of appa- 

 ratus or machinery does, and burners of every form should be cleansed by 

 using the instruments gratuitously supplied by your company. 



The most common causes of annoyance to consumers are, the allowing 

 of gas to remain in the distribution pipes during the summer, or when the 

 burners are not in use, and the displacements or imperfect laying of the 

 pipes within the buildings, allowing them to contain fluids. Not only are 

 the pipes liable to become coated by changes in the included gas, but, as it 

 acts on and solidifies all lubricating substances hitherto used, the keys of 

 stop- cocks become fixed and small openings stopped. Gas of high value 

 contains six per cent, of its volume in vapor, which can become fluid in 

 the pipes when they are exposed to the temperature of freezing water. 

 Hence depressions in the pipes soon collect fluids ; and unless the pipes de- 

 cline toivards instead of from the metre, the flow of the gas to the burner 

 is irregular. 



As the facts forming part of these replies might be supposed to rest on 

 individual authority, I will add, that the experiments have often been 

 made before the most distinguished scientific men of our country, and in 

 more than one instance submitted to the consideration and criticism of 

 those from abroad, with the expression of their entire approval. 



It is hardly necessary that I should allude to the quality of the coals 

 used in producing gas of the high value given by the experiments, as im- 

 pure coal docs not produce such gas. 



