6.4 DoolittWs Hydros tat. 



Art. VIII. — Description and specification of a Hydrostat, 

 or apparatus intended to secure a constant and uniform 

 supply of water in Steam Engine Boilers ; by Isaac Doo 

 little, of Bennington, State of Vermont.* 



Let a stop cock be placed in the feed, or supply pipe with- 

 in the boiler, so as to admit or intercept the passage of wa- 

 ter to the boiler at pleasure ; let a pinion be adapted, and se- 

 cured to the prolonged axis of the stop-cock, let a floating 

 body of convenient shape be placed within the boiler ; to 

 this body attach a vertical stem having a ratchet on one side 

 to gear into the above mentioned pinion ; let it be so geared 

 that when the water is at its proper height the cock shall be 

 closed and no more water admitted ; but as soon as the 

 quantity of water in the boiler shall be in any degree dimin- 

 ished, the floating body will descend with the surface of the 

 water, and as it descends the ratchet will open the cock and 

 admit a fresh supply. It is evident that the weight and vol- 

 ume of the floater must be proportioned to the effect inten- 

 ded to be produced : it is probable that the plano-convex 

 form will be most eligible ; as the segment of a sphere, with 



* Bennington Iron-Works, April 28, 1827. 



Benjamin Silliman, Esq. JVeto Haven. 



My Dear Sir, — Some two years since, when the boiler of a steam 

 boat collapsed on the Hudson, I communicated to the editor of the Troy 

 Centinel an idea which occurred to me of a method for preventing sim- 

 ilar accidents in future, if, as seems now to be the general belief, those 

 accidents are justly attributable to the want of a sufficient quantity of 

 water in the boiler at the time of their occurrence. 



I am not informed that any person has applied that idea to practice ; 

 and the late lamentable accident on board the " Oliver Ellsworth," has 

 led me to reflect more on the subject ; and feeling 1 , as I do, perfectly sure 

 that the very simple piece of mechanism which I have contrived, and 

 which can be applied, with very trifling expense, to any of the boilers 

 now in use, must and will fully answer the purpose for which it is inten- 

 ded, viz. to secure a constant and uniform supply of water in the boiler, 

 as -long as the engine is at work. I have determined to apply for a pa- 

 tent for the improvement ; and I now send you a copy of the specifica- 

 tion, with a sketch of the apparatus, which, if the subject matter seems 

 to you as important as it does to me, I beg you will insert in your Jour 

 nal, I am, Sir, with high respect and esteem, 



Your obedient servant, 



I. DoOLITTLE, 



