MECHANICAL AND USEFUL ARTS. 107 



The cost of the fuel is about Id. per hour for each stove ; the 

 "whole of them, however, are not used at one time, except in very 

 severe weather. The average cost of the whole fuel consumed 

 during the three winter months is not more than 5L per week. 



A witty canon (the Bev. Sydney Smith) is said to have given his 

 opinion that Middlesex itself might be as easily warmed as St. 

 Paul's Cathedral. Sir Christopher Wren appears, however, to have 

 actually provided ample flues for the warming, which are used in 

 the present operations, and the existence of which has greatly 

 assisted the engineers in carrying out their plans. — Times. 



LONDON SMOKE AND FOG. 



"What is often called fog, which darkens the metropolis in winter, 

 is, in reality, the smoke of millions of coal fires, which are much 

 increased in very cold weather. To prevent this, a Correspondent of 

 the Times recommends this simple plan : — Before you throw on 

 coals, pull all the fire to the front of the grate towards the bars, fill up 

 the cavity at the back with the cinders or ashes which will be found 

 under the grate, and then throw on the coals. The gas evolved in 

 the process of roasting the coals will then be absorbed by the 

 cinders, and will render them in an incredible degree combustible ; the 

 smoke will thus be burnt, and a fine, glowing, smokeless fire will be 

 the result. This rule should be enforced from the kitchen upwards. 



THE SEWING-MACHINE. 



The manufacture of clothing may be regarded as divisible into the 

 three stages of spinning, weaving, and sewing. Each of these opera- 

 tions may now be performed almost entirely without manual labour ; 

 but whilst the two former are entrusted to machines, the latter, though 

 a simple operation, is executed to a great degree by hand. No 

 country in the world approaches our own in the excellence of its 

 spinning and weaving machinery, or in the number and magnitude of 

 its factories ; but in sewing machinery, and in the number of our 

 factories of ready-made clothing, we are far behind the United 

 States. We have given the Americans the spinning-mule and the 

 power-loom ; they have sent us the sewing-machine. The two 

 former are of native growth ; the latter is an importation, and hence 

 may be partly attributed its comparatively slow progress in this 

 country. 



A\ hether the sewing-machine will add as largely to the wealth and 

 prosperity of this country as the spinning-jenny or the power-loom, 

 is a question which we shall not attempt to decide. We expect, 

 however, that the United States will maintain for many years her 

 present superiority over Great Britain in the manufacture and use 

 of sewing-machines. At the present time there are ten times as 

 many workmen, and ten times the amount of capital employed in 

 the manufacture of sewing-machines in the United States as in 

 Great Britain. The number of machines in use in the United States 

 cannot be less than 100,000; the number in use in Great Britain 



