SIK H. C. ENGLEFIELD 



It was before tion of experiments publifhed by the Academy Del Cimenlo, 

 Acad, del Ci- of Florence, in the year 1666, the identical experiment is 

 memo. defcribed in the following words : 



Narrative. 



Excellency of 

 their publica- 

 tion. 



The Acad, del 

 Cimento faid, in 

 mod books, to 

 have compiefl'ed 

 water in a globe 

 of gold. 



The globe was 

 filver, and ennv 

 pre fled by ham- 

 mering. 



" Ninth Experiment. 



" We were defirous to try whether a concave fpeculum, 

 expofed to a mafs of ice weighing 500 pounds, would reflect 

 any fenfible degree of cold on a very delicate thermometer of 

 400 degrees, placed in it focus. The refult was, that the 

 thermometer inflantly funk : but a doubt remained whether 

 the thermometer was acted on more by the direct cold of the 

 ice, or (hat reflected by the fpeculum. This doubt was re- 

 moved by covering the fpeculum : and certain it is (what- 

 soever might be the caufe) that the fpirit inftantly began to 

 rife again. Yet (till we will not prefume positively to affirm, 

 that this rife might not have been owing to fome other caufe 

 than the taking off the reflection from the fpeculum, all the 

 precautions not having been taken which might be confidered 

 neceflary to fecure abfolute affent to the experiment." — Saggi 

 di Naturali Efperlenze, page 176. 



I do not mean to affert that Mr. Pictet had feen this moft 

 excellent book, or that he borrowed from it without acknow- 

 ledging his obligation ; but the honour of having firft made 

 the experiment is certainly due to the Florentine philosophers. 

 It may not be foreign from the fubjeci here to obferve, that 

 the " Saggi," for perfpicuity, brevity, and that diffident cau- 

 tion fo eflential to the inveftigation of truth, is a model of 

 philofophical writing, not perhaps excelled by any book writ- 

 ten fince that time, and more admirable when we confider 

 the diffufe and obfeure itile fo much in fafhion in the works 

 of the learned at that period. 



2. Scarcely any trealife on natural philofophy has failed to 

 quote an experiment made by the academicians Del Cimento, 

 on the incomprefiibility of water inclofed in a globe of gold, 

 and lubmitled to the prefTurcof a fcrew prefs. Mr. Canton, 

 in his experiments on the fame fubjeel, publiflied in the 52d 

 vol. of the Phil. Tranf. fo fpeaks of it. You will probably be 

 furprifed when I affert, that the academicians did not try the 

 experiment with a gold globe, but one of filver; and that 

 they give a reafon for ufing filver in preference to gold, 

 namely, that the ductility of gold was fo great that it would 



extend 



