88' 



Laws of the 

 ftrufture of 

 cryftals, and 

 theory thence 

 re(ulting. 



THEORIES aV CRYSTALLOGRAPHY. 



heavens. By the very means by wliich the latter determine? 

 the future motions of the heavens, the Ahh6 decides which 

 forms are poflible and which are impolTible. It is thus by his 

 fimple and general law of cryftallization, ** the number of the 

 ranges of the fubtradive particles muil always be a coraraen- 

 furable quantity," that he has demonftrated the regular dode- 

 caHdron and the regular icofaedron to be im poflible forms in 

 mineralogy. As the immortal Newton, by having difcovered 

 the law of attra6lion to be *' in the inverfe ratio of the fquares 

 of the diftances," explained and calculated every thing in the 

 vaft regions of the firmament ; fo at the other extremity of the 

 creation the Abbe Haiiy, by means of a fingle law which he 

 has difcovered, explains the irregularities and calculates thofe 

 problematic formations with which the mineral kingdom had 

 hitherto aftonillied the natural philofopher. 



Laws, Sir, that refult from the ftudy of nature, enjoy this 

 ineftimable advantage, that they always lead to equations ; and 

 it is only by the help of equations (exprefled or underftood) 

 that quefrions can be lolved which relate to objects that can 

 be either counted or meafured. 



Of late, Sir, the word nature has been fo much abufed, 

 that I mu(i beg leave to ftate the prccife fenfe in which I wifli 

 to be underftood whenever I made ufe of that word in the 

 courfe of this letter. The Abbe Haiiy found it neceflary to 

 take a fimilar precaution at the beginning of the excellent 

 work (Traile de Phyjlque) he has lately publiflied. He fays : 

 ** This word Nature, fo frequently in our mouths, can only 

 be looked upon as an abridged expreffion, either for the refult 

 of thofe laws which the Great Creator has imprinted on 

 the univerfe, or for that aggregate of beings the works of his 

 hands. Nature, thus viewed in its true light, is no longer a 

 fubjed of cold and Herile fpeculation. The ftudy of its pro- 

 ductions, of its phaenomena, ceafes to be a mere exercife of 

 the mind ; it moves the heart, and ftrengthens the moral vir-. 

 tues in man, by awakening in his mind fentiments of refpedl 

 and admiration at the fight of fo many wonders bearing the 

 vifible characters of infinite power and wifdom." 

 With thefe fentiments I remain^^ Sir, your's, 



A. Q. BUEE. 

 y«/jf 13, 1804. 



OhfervatioM 



