his plans. No one hearing him explaining and seeing 

 him pointing out the parts would, if they did not see 

 his sightless eyeballs, even suspect his blindness. It 

 was a remarkable case of the cultivation of other 

 organs to supply the place of lost ones. 



He had evidently tried, or had tried for him, many 

 experiments with steam; his whole thoughts were on 

 that subject. He said he had satisfied himself that 

 the greatest economy was in using steam at very high 

 pressure, and also the greatest safety from explosion; 

 he even talked of using steam of 1.000 lbs. pressure 

 to the square inch, of the great reduction in the 

 weight of furnaces, boilers and steam engines for 

 ocean navigation that he should make, and that by 

 his system dangerous explosions would be an absolute 

 impossibility, as the steam for every stroke of the 

 engine would be generated as used. He claimed to 

 have demonstrated that the spheroidal state of water, 

 when thrown on heated metal, was entirely prevented 

 by using highly-heated tubes of great strength, and 

 maintaining in them an attenuated vapor at a pres- 

 sure of not less than 175 lbs. This was done by the 

 escape valve being loaded to that pressure. 



His plan was to inject into these tubes just the 

 quantity of water required to generate the steam at 

 the pressure wanted and required to fill the cylinder 

 and make the stroke. He had another modification 

 that had grown out of the difficulty of regulating the 

 jets of water with absolute certainty. This was to 

 keep his heavy, strong and highly-heated tube- 

 generators full of water, and to allow just so much 

 highly-heated water to escape and flash into steam 

 as was required for each stroke of the engine. I do 

 not recollect the exact mode he proposed to accomplish 

 this. 



Toward the latter part of the time father was con- 

 nected with Mr. Perkins, Hawkins had succeeded in 

 getting, by subscription, what he thought would en- 

 able him to demonstrate his theories. This subscrip- 

 tion was headed by two retired merchants from 



Charleston who had settled in Philadelphia, and had 

 known Hawkins in his early days; part was by shops 

 in the shape of work; a brassfounder subscribed the 

 brass castings; a coppersmith the steam pipes, etc. 

 Hawkins was given the use of bench and tools in the 

 P. & S. shops, and there he brought the different 

 parts of his engine together, which he erected under 

 a shed in a yard in the vicinity. 



Perkins took great interest in the work as it went 

 on, and, no doubt, gave him much aid. 41 On the 

 first trial of this engine the soft solder of two wiped 

 joints of the small copper steam pipe melted, and it 

 blew apart in a few minutes after the engine was 

 started. Here Hawkins' trouble commenced. For 

 these copper pipes he substituted musket barrels, 

 joining them by conically counter-sinking one and 

 tapering the other to fit into it, drawing them together 

 by clamps and bolts. 



There did not seem to be any serious trouble with 

 his generator, but the great heat of his high-pressure 

 steam burned out the hemp packing of his piston and 

 piston rod. Then came a long series of experiments 

 with metallic packing, which at the high heat, for 

 want of lubrication, fastened to the cylinder. Then 

 followed a most ingenious device. He put on a larger 

 steam cylinder to work with lower pressure, a con- 

 denser to give him hot water from the escape steam; 

 simultaneous with the flash of highly-heated steam, 

 or water flashing into steam, hot water was injected, 

 reducing the temperature and increasing the volume 

 of steam at a lower pressure. 



He had a scheme of open and single-stroke engines, 

 with a plan of lubricating, that I do not remember, 

 nor do I recollect to have ever heard him allude to 

 using high steam for rapid shooting, as was exhibited 

 by Perkins with his steam gun in London. But he 

 had a vision that he liked to dwell on and talk of for 

 protecting such harbors as New York that I cannot 

 better describe than by using his own words as near 

 as I can recollect them. 



He would say that: "Ascertaining the narrowest 

 part of the channel, I choose the position for my 

 battery of generators, always kept heated ready to be 



11 An account of the demonstration by Perkins of the Hawkins 

 boiler, before Charles Willson Peale, Robert Hare, and several 

 others is in the Memoirs, book 20. pp. 5-1 1. Mention of 

 further developments in Philadelphia of the Hawkins boiler, 

 involving the dentist Plantou, is made in ScHARF and WesT- 

 cott (cited in note 14 above), vol. 3, p. 2263, and in Charles 

 Coleman Sellers (cited in note 20 above), vol. 2, pp. 397-398. 



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