GAS AND OIL ENGINES 



steam power used was 2,185,458 horse-power out of a 

 total of 3,410,837, or 64.1 per cent; in 1890 out of an 

 aggregate of 5,954,655 horse-power, 4,581,595, or 76.9 

 per cent was steam; while in 1900 steam figured to the 

 extent of 8,742,416 horse-power, or 77.4 per cent, in a 

 total of 11,300,081. This increase in thirty years, from 

 51.8 per cent to 77.4 per cent of the total power, shows 

 how much more rapidly the use of steam power has 

 increased than other primary sources of power. 



"The tendency toward larger units in the use of 

 steam power is shown inadequately by the increase in 

 the average horse-power per engine from 39 horse- 

 power in 1880, to 51 horse-power in 1890, and 56 horse- 

 power in 1900. 



"The tendency toward great operations which has 

 been such a conspicuous feature of industrial progress 

 during the past ten years, has shown itself strikingly in 

 the use of units of larger capacity in nearly every form 

 of machinery, and nowhere has this tendency been more 

 marked than in the motive power by which the machinery 

 is driven. At the same time there has been an increase 

 in the use of small units, which tends to destroy the true 

 tendency in steam engineering in these statistics. For 

 example, a steam plant consisting of one or more units 

 of several thousand horse-power may also embrace a 

 number of small engines of only a few horse-power each, 

 the use of which is necessitated by the magnitude of the 

 plant, for the operation of mechanical stokers, the 

 driving of draft fans, coal and ash conveyors, and other 

 work requiring power in small units. On this account 

 the average horse-power of steam engines in use at 



