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LXXVII. On a Hydro-pneumatic Pump. By Mr. S. Seaward. 

 To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 



FROM the Notices to Correspondents contained in a late 

 Number, I observe that the letter I had the honour of ad- 

 dressing to you, in vindication of my claim to the invention of the 

 Hydro-pneumatic Pump, has been refused insertion in your va- 

 luable work, partly because it did not offer any " proofs." 



I beg to acquaint you that, in consequence of my being sta- 

 tioned in a distant part of Cornwall, I am precluded, for the 

 present, from collecting the necessary evidence, which on my 

 return to London I shall have no difficulty in obtaining, to 

 the full establishment of my claim. 



In the mean while permit me to offer to your notice two or 

 three facts which can be easily verified. 



Having conceived the idea of compressing gas by the me- 

 dium of a liquid body, I submitted my first ideas to paper, in 

 the form of sketches, long before I had any communication 

 with Mr. Martineau on the subject. This document is now 

 and constantly has been in the possession of my brother, who 

 will be happy to show it to any person who is inclined to give 

 it an examination. It is true my first plan differed materially 

 in form and size from the pump afterwards made, although 

 in principle it will be found substantially the same. 



I afterwards, with the advice of my brother, arranged and 

 planned the pump in all its essential features, both as to size 

 and disposition of parts, exactly as described in your Number 

 far July. 



This plan I submitted to Mr. Martineau, and explained to 

 him the nature of the machine, with its intended operation; 

 and now I can solemnly aver, that up to this time neither my- 

 self nor any person whom I consulted had the slightest idea 

 that any thing of the kind had ever been suggested before. 



However, I was now informed that Mr. David Gordon of 

 the Portable Gas Company had already proposed a pump on 

 similar principles, and had published his ideas on the subject, 

 about four years ago, in the Repertory of Arts. As soon as 

 I was acquainted with this fact, I waited upon that gentleman 

 to ascertain whether he intended to pursue the idea any fur- 

 ther ; he candidly informed me he did not, but wished me suc- 

 cess in mv endeavours, as lie approved my plan. _ 



From this period, no time was lost in proceeding with the 

 pump, which was made and completed entirely under my ma- 

 nagement and direction, as must be notorious to everybody 

 in Mr. Martineau's factory. If the above facts be correct, — 

 Vol 64. No. f}20. Dec. 1824. 9 K and 



