246 



REPORT — 1880. 



eqnal to 16 standard speiin candles, when burned at the rate of 5 cubic 

 feet per hour in Sugg's No. 1 London Argand Burner, and the results 

 obtained are given in the following tables. The standard candle, as in the 

 case of cannel gas, is one consuming 120 grains of sperm per hour. 

 The photometric apparatus and the method of testing employed were 

 about the same as those described in the first part of this report. The 

 two jets representing the candles were supplied with gas from a separate 

 gas-holder, always kept under exactly the same pressure. The gas con- 

 sumed in the burners to be tested was also supplied from a separate 

 holder, to which any required pressure could be readily applied. For 

 comparison, the results obtained are calculated into the amount of light 

 for a consumption of 5 cubic feet per hour in each case. 



Of the four classes of burners described in the first part of this report, 

 the ' rat-tail ' or single-jet burner is now seldom or never used for common 

 gas for lighting purposes. The union-jet or fish-tail burner, the batwing 

 burner, and the Argand burner, or modifications of these various burners, 

 are now almost exclusively used. These burners and their modifications 

 have for the most part been already fully described, and it is therefore 

 unnecessary to repeat these descriptions at any length. 



Messrs. Bray and Co. manufacture a great variety of flat-flame burners. 

 Their ' Regulator ' burner checks the pressure of gas in the mains by 

 means of layers of muslin inserted in the burner. Their ' Special ' 

 burner, in addition to the layers of muslin, has also a piece of a kind of 

 porcelain, containing a round hole of less area than the exit orifices, 

 placed below the muslin, through which the gas passes into the burner. 

 These ' regulator ' and ' sjDecial ' burners are made in three different 

 forms — union-jets, batwings, and a modification of the batwing called a 

 'slit-union.' The latter, owing to a peculiar chambering out of the head 

 of the burner, forms a narrower and liigher flame than the ordinary bat- 

 wing, and is therefore better adapted for use in globes. This form of 

 batwing is also made by various other makers. Besides the burners 

 already mentioned, Messrs. Bray and Co. also make each form of burner 

 of high lighting power and of medium lighting power, and they recom- 

 mend the medium lighting power burners in preference to the others for 

 general use, as having less tendency to smoke. 



Of these burners of Messrs. Bray & Co., the following have been 

 selected for trial : — 



