1 83 Hints for the Formation of 



accuracy of refuit, as to the quantity of metal, will not al- 

 ways be obtained ; but a verv comprehenfive knowledge will 

 be formed of the nature of the earthy mixtures, and the 

 ftrength and fufihility of the metal. Once in the poflTeflion 

 of thcfc, it will be no difficult matter to fuperadd a portion 

 of earths requifite for perfect redudion. In two fimple ex- 

 periments,, therefore, not only the real quantity of metal con- 

 tained in the ore is obtained, but its prefumptive ftrength 

 and fuiibility developed in a gr^■at■. meafure prior to its appli- 

 cation to the purpofes of the blaft-furnace. 



In order to facilitate this operation, and to compare the 

 various degrees of heat in which different experiments are 

 effetSled, I conftruifted a pyrometer upon the principle of the 

 cxpanfion of metal b^■ heat ; a reprefentation of \xhich, and 

 a. defcription of its ufe, will form an article for the next 

 Nuniber of the Philofophical Magazine. 



XII. Agenda, or a Collecl'tcn of O'fervations and Refearfbes 

 the Re/ulls of ■which may ferve as the Foundation for a 

 Theory of the Earth. By M. De Saussuhe. 



[Continued fiom page 71.] 



CHAP. XVII. 



Glfervations to he tnade en the Remains and Vefliges of orga- 

 nized Bodies fund in the Earth, in Mountains, and at 

 their Surjaee. 



1. X HEIR nature, bulk, and quantity; the extend, depth, 

 ai;d other diraenfions of the ftrata where they are found *. 



2. Their prefervation. Whether entire or broken, decom- 

 pofed or not ; (hells with their pearly covering (nacre) ; their 

 colour ; remains or trace* of their fifli, or their fkin if there 

 be any, . o deduce, if po Jiolc, from thefe data, fome idea 



'" T. A. if forme ' of tries, to maik down the 'irefli m of the ftrata ; 



and "huthtr ^hev an p'aceil hoiizontaHy, or inclined either towards the 



fummic or me routs. C 



of 



