a^O French National Injlituie, 



In the fitting of June 2, profeflbr Frank read a paper on 

 the queftion lately propofed by Meffrs. Anton and Krefch- 

 nian — whether tlie orit>in of Bards and the Druids can be 

 jullly afcribed to the old Germans? The author is of the 

 opinion of thofe who anfwer this queftion in the negative. 



FRENCH NATIONAI. INSTITUTE. 



Account of the labours of the French National Inftitute 

 <iuring the latt three months of the year 9. 



[Continued from p. iSS ] 



Ohfervathns made dur'mg three Years on the metallic Chains 

 jh/'pended J'roni the Dome of the Pantheon to afcertain anj' 

 /jorizontal or vertical Change that might take place in the 

 Building. By C. Prony. 



The late niiniller of the interior, Benezech, having ap- 

 pointed a conmiifficn to rcfume the labours of thofe before 

 ertablidied for examining the Pantheon, and pointing out 

 the means that might be neccflarv for its prefervation, 

 C. Prony, member of this commiihon, read an interefting 

 memoir on this fubjeot, which was heard with great atten- 

 tion. Five metallic chains, compofed of links each 3*937 

 inches in length, are fufi)endcd below the cupola of the Pan- 

 theon. Four of tliefe chains are parallel to the vertical fur- 

 fiices of the planes of the pillars ; the fifth is attached to 

 the centre of the exterior dome, and hangs down near to 

 the ground. The centres of five horizontal circular plates 

 are made to correfpond very exacllv to the points where the 

 weights with which each chain is loaded terminate. Thefe 

 plates are raifed on vertical graduai^ed ftalks, which rife and 

 fall freely in I'ockcts, and which can be fixed to any height 

 by means of fcrews. Concentric circles are traced out on 

 each platCj and meteorological inllruments placed indifferent 

 parts of the cditlce indicate the differences of temperature. 



Chains fufpended in this manner can fink down only in 

 confequence of three caufes. ill, The dilatation of the metal, 

 which would augment their volume and the length of their 

 mafs : 2d, Elongation, occaiicncd by an extenfion which a 

 certain weigiht nii2;ht give to that length where the fyftem is 

 interrupted by links: 3. The partial or total fmking of the 

 ctlilice. 



The elfefts which changes of temperature might produce 

 on a metallic iVltcm, interrupted by links, were examined 

 with as much accuracy as it is poftible to attain to in re- 

 fearches of this nature, with an inltruinent invented by that 

 eminent artilt Ramfdcn. Lavoilier and Laplace repeated 

 6 thcfe 



