REAR-ADMIRAL G. W. MELVILLE, U.S.N. 185 



plosion.* In fact, the list of boiler explosions, with their attendant 

 loss of life and property, is a list of failures of the shell-boiler. 

 Admiral Melville brought this 'new' boiler into permanent employ- 

 ment a hundred years after Stevens and made its valne and necessity 

 evident. The battle-ship or cruiser of to-day could not be constructed 

 of equal speed, and equal efficiency of armor and armament, without 

 it, and all navies are now adopting it. It gives a minimized weight 

 and space for the unit of power, is safe against the disastrous explosions 

 characterizing so frequently the termination of the work of the shell- 

 boiler, and it is economical. It may be employed for pressures of any 

 degree of intensity . The battle-ship of to-day could not attain its 

 actual effectiveness without its employment, at least as a battery for 

 high speeds. At cruising speeds, the older boiler is often retained; the 

 later type being brought into operation when driving the ship up to 

 emergency speed. The water-tube boiler requires more skill in han- 

 dling than the fire-tube. 



Melville introduced the triple-screw system for large ships, in which 

 it was becoming difficult to secure safe construction of the enormous 

 propeller-shafts demanded, and where it seemed to him desirable to 

 secure a better hold upon the water by enlarging the area of the current 

 utilized in propulsion. The success of the Columbia and the Minne- 

 apolis, fast cruisers, was? complete, breaking the record for naval craft 

 of large size and exceeding by a knot the speed anticipated even by 

 their designer. He introduced the 'repair-ship,' a floating machine- 

 shop, and the 'distilling ship,' in the war with Spain, as adjuncts to 

 the fleet, innovations, both, of great value, often of vital importance. 



In the details of his work, the chief of bureau has always exhibited 

 the most thorough familiarity with its scientific side, and his plans 

 have always involved the employment of every expedient known to 

 science for promotion of efficiency. He has advocated increased 

 thermodynamic range, higher ratios of expansion and greater piston- 

 speeds for his engines, to give increased thermodynamic efficiency; 

 has made effective provision against those extra-thermodynamic wastes 

 which constitute the most serious tax upon heat utilization and has 

 adopted every sound system of improvement known to modern science 

 as bearing upon his work. 



One of his most important movements was that in promotion of 

 the merging of the old engineer corps of the navy into the line. The 

 battle-ship has long been recognized as what the writer has called the 



*' Report to American Institute,' 1871, Ibidem. 



t Water-tube boilers have been built to sustain from one to two thousand 

 pounds on the square inch. The boiler of a quadruple-expansion experimental 

 engine constructed as ' thesis-work ' in Sibley College, and the engine attached 

 which holds the world's record for economy in its class, has been operated at 

 above one thousand pounds. 



