350 Dr George Wilson on the Early History of the 



liar with the appearance of the great pneumatical engine. 

 After Hooke's death, in the beginning of last century, there 

 was none living likely to have a special interest in its pre- 

 servation. Some zealous curator, if it then existed, would 

 sweep it into a corner, or sweep it away as lumber. Mr 

 Weld's original air-pump results from the combination of two 

 quite unconnected facts ; the one, that Boyle gave the Royal 

 Society an air-pump in 1661 ; the other, that the Society now 

 possesses an old air-pump. That the latter is not the ori- 

 ginal great pneumatical engine does not admit of doubt. 

 Boyle, moreover, is not known to have presented more than 

 one air-pump to the Royal Society. Unless, therefore, there 

 is evidence of the most explicit kind to shew that the double- 

 barrelled instrument was once the property of that philoso- 

 pher, we must hold it as highly unlikely that it ever was in 

 his hands. It will presently appear, that it probably does 

 not belong to his age, but is an air-pump of the eighteenth 

 century. 



A few words will conclude the early history of the English 

 air-pump. Papin's double pump does not appear to have been 

 directly copied by English instrument-makers, so that its 

 stirrup arrangement, in particular, was practically unknown. 

 I have been unable to find any allusion by Hooke himself to 

 his having constructed a double-barrelled air-pump ; nor has 

 any reference been given by those who affirm that he did, to 

 any existing instrument, or drawing, or account of it. It 

 would be dangerous, however, to assert an absolute negative 

 on this point, for Hooke's papers are very numerous, are im- 

 methodically arranged, ill edited, and not easily consulted. 

 Yet, had there been any notorious declaration of Hooke's 

 on the subject, it would have been quoted by those who fa- 

 vour his pretensions. On the other hand, Waller, who sets 

 up a well-founded claim on Hooke's part to Boyle's air-pump, 

 limits the claim to the one-barrelled pneumatical engine of 

 1659. Boyle and Hooke were, from first to last, attached 

 friends, and in constant communication with each other. 

 Had Hooke devised a new air-pump, Boyle was the first per- 

 son to whom he would have shewn it ; and, even if he had 

 not explained its construction to Boyle, the latter could not 



