LETTER VIL 171 



When it was firft taken out of the Horfe, the 

 rough Side of it was foft, and was twelve months 

 in hardening, whereas the fmooth fide was as hard 

 as it is now, when taken out. It weighs (in A- 

 verdupoife Weight) two Pounds and a half, and 

 two Ounces, being of the fize, as well as fhape, 

 of a Horfe's Kidney, and of a very deep BufF- 

 colour. In Chili^ upon the Confines of Peru^ 

 about South Latitude 25, is a River called the 

 River of Salt, becaufe it is fo fait, that it cannot 

 be drank, and petrifies what is thrown into it. 



25. Let us now advance to our Fourth con- 

 clufive Point, viz. That it is even poffible for us to 

 invent Artificial Stones, which will be very dura- 

 ble. And by Artificial Stones, I mean pulverized 

 Stone, or Gravel, or Sand, well tempered and 

 mixed with Putty, or any other ftrong Cement^ 

 like that which joins together the feveral parts 

 of a French Mill-ftone, and does really become as 

 hard as the Stone itfelf, moulded into what fhape or 

 bulk we pleafe, and afterwards dried, either by the 

 natural heat of the Sun, or by Air in the Shade 

 only, or elfe by the artificial Heat of Fire in Fur- 

 naces, that may be contrived for that ufe. 



26. Such are thofe Stones, in the Lids of fome 

 SnutF-Boxes, that are fold pretty commonly at 

 pur London Toy-fliops. Several of my Acquain- 

 tance, at their return from Italy ^ fhewed me fome 

 pf the t>eft fprj: pf thepii and for farther autho- 

 rity. 



