110 



REPOKT 1878. 



The burners at present in nse may be divided into the four following 

 classes : — 1st, Cockspur or rattail ; 2nd, Union or fishtail ; 3rd, Bat- 

 wing ; 4th, Argand. Of each of these there are a number of modifica- 

 tions. 



The cockspur or rattail burner is the simplest possible form of gas 

 jet, and it was at one time the only one used for burning gas. It may 

 be made by simply drawing out a piece of glass tube and breaking off 

 the point so as to leave an orifice, having a diameter of 1 millimetre or 

 less ; but it is usually constructed of cast iron, which is drilled out as wide 

 as possible from the bottom, leaving only a thin shell, which is then bored 

 with a fine drill. Two sizes of these were tested, No. 1 having an orifice 

 of about -6, and No. 2 of about 75 millimetre. These jets are used in 

 Glasgow for lighting common stairs, and the larger size were formerly 

 employed for street lamps, but are now discarded in favour of union jets. 

 The following are the results with 26-candle gas : — 



These figures show that even with the larger jet no more than 60 per 

 cent, of the real value of the gas can be obtained. Various modified 

 forms of the jet were tried, some having " adamas " tips, and contracted at 

 the bottom or otherwise obstructed, so as to diminish the pressure at the 

 point of ignition, but they did not show any marked superiority over 

 those referred to above. 



When two rat-tails are held at a right angle to one another, the lights 

 •coalesce and form a flat sheet of flame. When this discovery was first 

 made, two burners were fitted up in this way ; but soon a single burner 

 was contrived which combined the two, and hence was called a "union " 

 jet : it is also known as a fishtail, from the resemblance of the flame to 

 the tail of a fish. It is a short cylindrical tube with a flat top in which 

 the two orifices are drilled at about 90° to one another, and meeting in 

 the centre. The union jet is much improved by substituting for the 

 metal top porcelain or stoneware, the principal advantage gained being 

 that the orifices remain clean and constant in size, while those of iron 

 gradually rust up and require to be frequently cleaned in order to give 

 a satisfactory light, and are consequently enlarged. Some fishtail 

 burners are made entirely of a kind of stoneware or of steatite, but these 

 are troublesome to remove when they get broken. The best form of 

 burner is that with a brass body and porcelain top. Such burners are 

 made by Leoni of London, Bray of Leeds, and other makers ; but usually 

 with some means of reducing the pressure. The fishtail burner is not 

 suited for burning at a high pressure, under which the two flames refuse 

 to spread out into a flat sheet but form an irregular flame, at the same 

 time emitting a most disagreeable hissing or blazing sound. This effect 



