S/A' WILLIAM SIEMENS, F.R.S. 189 



t n>u I ile ; that in lighting it is very agreeable to turn the gas on or 

 off as needful, and to be able to keep up the fire for half a day 

 without touching it. Many friends when they have come into the 

 room have said, "What a magnificent fire." 



The cost also I have been able to ascertain by this time. For 

 tin- first quarter of the present year, in the five large grates, 

 including the drawing-room, my own study, and the dining-room, 

 where a fire is maintained nearly the whole day, the consumption 

 of gas amounted per grate to 6,HOO cubic feet, being of the value 

 of one guinea, or of one ton of coal when at its cheapest in 

 London. I am quite sure I have saved more than a ton of coal 

 in each grate, even after debiting myself with the consumption of 

 coke, which amounts to about one-third the consumption of coal. 

 Taking it all in all, it is a cheap fire, and certainly it is perfectly 

 smokeless. I am glad to say that several of the leading grate- 

 builders have taken up the construction of this grate, and I believe 

 at this present moment there are several hundreds of them in 

 actual use. 



I have adopted the same principle for intensifying the light of 

 an ordinary argand gas-burner, Plate 35. Through the centre of the 

 burner a stem of copper projects, which is bulged out cup-like, at its 

 upper extremity, and is connected at its lower extremity with a 

 cylindrical box of copper, of high conductive power. The 

 cylindrical vessel is perforated all over, and round it ten layers 

 of copper-wire gauze are wound. The bottom also is closed by 

 ten discs of wire gauze. The burner is mounted in the ordinary 

 w.ay with a glass chimney, but at the point of the flame the 

 bulged portion of the rod, filled up with fire-clay, gathers up 

 heat, and conducts it downwards to the wire gauze, whilst the 

 current of air is drawn in by the flame itself, and is heated in its 

 transit through the wire gauze, to a temperature of from about 

 500 to 700 Fahr. By this simple arrangement the intensity of 

 the gas flame can be very nearly doubled. In fact, according to 

 one experiment, it was rather more than doubled, measured 

 photometrically ; and at the same time a flame of much whiter 

 character is obtained. 



TJie President: Do you remember what is the illuminating 

 power of such a burner ? 



Dr. Siemens : In using ordinary gas we get from this burner 



