SIR WILLIAM SIEMENS, F.R.S. 239 



minute. To produce the same amount of light by gas takes 

 200 Argand burners, consuming 16 cubic feet of 20-candle gas 

 per minute, which consumption represents 15,000 heat units. 

 Some additional lu-at will be produced in the electric arc, however, 

 by the combustion of the carbon electrodes, which consumption 

 amounts to G'3 grains of carbon per minute, and will produce in 

 combustion 12'5 heat units. The total amount of heat produced 

 by the electric arc is, therefore, 130 + 12'5 = 142', r > units per 

 minute, or rather less than 1 per cent, of the heat developed with 

 the same amount of light by means of gas. Gas light produces, 

 moreover, the further inconvenience of displacing the oxygen of 

 the air by carbonic acid, and by a minor, but still very sensible 

 amount of sulphurous acid. 



If this calculation militates against gas as an illuminating agent, 

 it proves, on the other hand, its great value as a heating agent ; 

 and just now, when so much is said about the smoke nuisance, I 

 may be allowed to add a few words on that subject. For upwards 

 of twenty years I have been actively engaged upon the develop- 

 ment of a system of working furnaces for the manufacture of 

 iron, steel, glass, &c., by means of gas fuel produced in a simple 

 gas-generating apparatus. Some thousands of these gas producers 

 are in operation, and furnish daily proof that gas may be used 

 with economical results ; and the smoky factory chimney, 

 where it still exists, proves simply a disregard for principles of 

 economy. In the year 1858 I was anxious to take a further step 

 in the same direction in proposing to supply towns with heating 

 gas, and, having induced the Town Council of Birmingham to 

 support my plans, measures were taken to obtain Parliamentary 

 power to carry them into effect. It was intended to separate the 

 two constituents of coal by a comparatively inexpensive method, 

 supplying gas of low illuminating, but high heating power to 

 consumers at a cheap rate, and reserving the coke for use in loco- 

 motive engines and stoves, for which purpose it is eminently better 

 suited than raw fuel. Unfortunately, the bill was thrown out by 

 a Committee of the House of Lords, in consequence of the oppo- 

 sition of the existing gas companies, and the proposal has remained 

 in abeyance ever since. While it is admitted by many that gas 

 fuel can be used advantageously for heating furnaces, there still 

 exists great objection to its use upon the domestic hearth, which 



