VdliV XV.] PHILOSOPHICAL TRANSACTIONS. 231 



Part of a Letter, containing a further Account of the Aqueduct near Versailles^* 



&c. N" 1/6, p. 1206. 

 Labourers are every where at work about Versailles, making magazines for 

 the waters to be conducted thither; as, one upon the mountain of Montboron 

 already cut, which will have 2200 perches of surface, each perch being 1 8 

 French feet; and 12 feet in depth. In another place, much lower, will be an- 

 other magazine, to receive the waters of many pools. In the valley of Buc will 

 be an aqueduct, the middle of which will be raised 22 fathoms high, for con- 

 veying the pools of Sarle. This aqueduct is 300 fathoms long, and passes 

 through two mountains, which have been cut through for that purpose. The 

 valley also on both sides of the aqueduct is raised 1 1 fathoms high, to make 

 passages. 



An aqueduct also is making near the tower of stone, where the mills raise 

 the water, which now will pass without force to the top of the mountain, and 

 be there part of it distributed into several very large cisterns, which are making 

 above Marli for that place. 



The elevation of the aqueduct of Mantenon is now set forth at only 256o 

 fathoms, whereas it was designed to be carried on more than 8000 fathoms, and 

 the remainder to be made of earth, which must be brought thither. These 

 "2560 fathoms contain 242 arcades, the aperture of which is 6j- fathoms, and 

 the face of each pillar, sustaining the arches, 4 fathoms ; there will be then on 

 the side of Mantenon 33 single arches, afterwards 71 double ones, being 

 one arch upon another, then 46 treble ones, which will generally be 2l6-i. feet 

 high, viz. up to the floor of the channel ; afterwards 72 double ones ; then 20 

 single, reaching to the mound of earth which is to be 50 feet high. 



From the ground up to the second arcade are l6 fathoms, from the second to 

 the third, or upper arcade, are 14 fathoms, which arcades are double in number 

 to those they stand upon, and 6i fathoms more to the floor of the channel, 

 which will at least be 6 feet high, besides the parapet. 



The pillars at the ground are 8 fathoms thick, but what with the slopes and 

 shortenings which are made in every story ; the top where the channel goes 

 will be but 20 feet broad : there will be also at each pillar a buttress jetting out 

 I fathom, and 2 fathoms wide. 



Account of a Book. 

 Frederici Hoffmanni Fred. Fit. M. D. Exercitatio MedicO'Chymica de Cinnabari 

 Antimonii. Lugd. Batav. l685, Qvo. N° 176, p. 1208. 

 The author of this treatise gives an exact account of the manner of preparing 



* See vol. II. 



