SCIENCE IN RELATION TO THE ARTS. 213 



working cylinder, which has to be cooled artificially in order to keep 

 its temperature down to a point at which lubrication is possible ; this, 

 together with frictional loss, can not be taken at less than one half, and 

 reduces the factor of efficiency of the engine to one fourth. 



It follows from these considerations that the gas or caloric engine 

 combines the conditions most favorable to the attainment of maximum 

 results, and it may reasonably be supposed that the difficulties still in 

 the way of their application on a large scale will gradually be removed. 

 Before many years have elapsed we shall find in our factories and on 

 board our ships engines with a fuel-consumption not exceeding one 

 pound of coal per effective horse-power per hour, in which the gas- 

 producer takes the place of the somewhat complex and dangerous steam- 

 boiler. The advent of such an engine and of the dynamo-machine must 

 mark a new era of material progress at least equal to that produced by 

 the introduction of steam-power in the early part of our century. Let 

 us consider what would be the probable effect of such an engine upon 

 that most important interest of this country the merchant navy. 



According to returns kindly furnished me by the Board of Trade 

 and " Lloyd's Register of Shipping," the total value of the merchant 

 shipping of the United Kingdom may be estimated at 126,000,000, 

 of which 90,000,000 repi-esent steamers having a net tonnage of 

 3,003,988 tons ; and 30,000,000 sailing-vessels, of 3,688,008 tons. The 

 safety of this vast amount of shipping, carrying about five sevenths of 

 our total imports and exports, or 500,000,000 of goods in the year, 

 and of the more precious lives connected with it, is a question of para- 

 mount importance. It involves considerations of the most varied kind: 

 comprising the construction of the vessel itself, and the material em- 

 ployed in building it ; its furniture of engines, pumps, sails, tackle, 

 compass, sextant, and sounding apparatus, the preparation of reliable 

 charts for the guidance of the navigator, and the construction of har- 

 bors of refuge, light-houses, beacons, bells, and buoys, for channel navi- 

 gation. Yet notwithstanding the combined efforts of science, invent- 

 ive skill, and practical experience the accumulation of centuries we 

 are startled with statements to the effect that during last year as many 

 as 1,007 British-owned ships were lost, of which fully two thirds 

 were wrecked upon our shores, representing a total value of nearly 

 10,000,000. Of these ships 870 were sailing-vessels and 137 steamers, 

 the loss of the latter being in a fourth of the cases attributable to col- 

 lision. The number of sailing-vessels included in these returns being 

 19,325, and of steamers 5,505, it appears that the steamer is the safer 

 vessel, in the proportion of 4 -43 to 3*46 ; but the steamer makes on an 

 average three voyages for one of the sailing-ship taken over the year, 

 which reduces the relative risk of the steamer as compared with the 

 sailing-ship per voyage in the proportion of 13 # 29 to 3'46. Commer- 

 cially speaking, this factor of safety in favor of steam-shipping is to a 



