e PHILOSOPHICAL TRANSACTIONS. [anNO 1755. 



allow wax would infallibly do; and also to give it such a body, as that, when 

 dry, it might stand the injuries of the weather; for the heat of the sun would 

 melt simple wax, and make it run down in streams, without an admixtion of 

 something else to give it the necessary firmness. 



That the ancients were well acquainted with enamel painting cannot be doubted, 

 since there are great numbers of their enamel pieces in the cabinets of the curi- 

 ous in many places. There is one, which is a Roman cup curiously enamelled 

 on brass, found at Froxfield, in the possession of Lord Hertford; there is a 

 Roman enamelled platter on the same metal, probably belonging to the cup, with 

 figures and inscriptions curiously painted in the enamel, of Leg. ii, Aug. and 

 Leg. xx.vv. in Britain, a drawing of which Dr. Stukely made in its colours (see 

 Buonoroti's Osservazzioni on the Duke of Tuscany's Medallions). And the 

 Doctor has now an enamelled fibula of the same kind of workmanship. Nor 

 are there wanting cups with portraits of some friends enamelled at the bottoms, 

 which were used inter pocula, to drink to their memories; and it is probable, 

 that the enamelled ware of cups, platters, ewers, and such like, which the great 

 Raphael was concerned in making, many of which are now in England, were 

 made in imitation of the ancients ; since in every other part of his art, he was 

 so close a follower of their most correct works, and since the colours and appear- 

 ance are exactly the same in his, that are on those ancient pieces mentioned, 



CII. Of the late Earthquakes felt at Maestricht, in a Letter from Mons, Ver- 



nedcj Pastor of the fVallon Church there. Translated from the French, 



p. 663. 



The number of shocks has been very considerable here. From the 18th of 

 February to the beginning of April, 1756, no day passed in which one was not 

 felt, often more. Mons. Hoffman has remarked about 80 distinct ones. 



There were even some successive hours, in which the earth was scarcely at all 

 quiet; but these were only tremors- The strongest shock was that of the 18th 

 of February. It continued about a minute and a half. The next in degree to 

 this was that on the day after Christmas day, which lasted about a minute. 

 There were some others no less violent, but of much less duration. 



All the shocks were not of the same kind. The motion was undulatory in 

 those of the 26th of December, and 18th of February; but the undulations on 

 the former of these days were longer than those on the latter. At other times 

 there were observed only a rising and sinking again, and most commonly a shak- 

 ing on one side. During the most violent shakings there were some kind of 

 flashes of lightning. The whole was preceded by a groaning under-ground, 

 which, when the shocks were weakest, seemed most like the noise of a cart 

 deeply loaded, heard at a distance; and when they were strongest, to that of a 



