6 



PREFACE TO THE 



The humble Hyssop on the wall, as well as the 

 lofty Cedar, shows plainly that an Almighty and 

 an All-wise hand has formed it. Nature's works 

 are all complete ; and the more minutely we ob- 

 serve, investigate, and consider them, the more 

 we must admire the wisdom, and adore the good- 

 ness of the munificent and august Creator. * 



and which is properly the contemplation of Divine Wisdom in 

 the works of nature." 



Dr. Burnet's Theory of the Earth, vol. i. book i. chap. v. 

 * Dr. R. Watson, in his Chemical Essays, vol. i r p. 86. has 

 thus judiciously observed the surprising and beautiful regularity 

 of nature. 



" There are a great many circumstances relative to the man- 

 ner in which different salts crj^stallise, which cannot be insisted 

 on in this place ; one thing deserves particularly to be remarked^ 

 that every salt in crystallising, invariably assumes its own pe- 

 culiar form. You may dissolve common salt, or saltpetre, a 

 thousand times, and crystallize them as often by evaporating 

 or cooling the water in which they are dissolved, yet will you 

 still find the common salt will be constantly crystallised in the 

 form of a cube, and the saltpetre in the form of a prism ; and 

 if you examine with a microscope such saline particles as are 

 not visible to the naked eye, you will observe these particles to 

 be of the same shape with the larger masses. The definite 

 figure appropriate to every particular species of salt, may admit 

 a little variety from the accidental admixture of other bodies, 

 or from some singular circumstances attending the evaporation 

 and crystallisation of the solution ; but these varieties are foreign 

 to the nature of the salt, and are not greater than what attend 

 almost every species of vegetables, and even of animals, from 

 change of food and climate. 



" Here a large field of enquiry opens to our view ; and though 

 it be better, as Seneca has it, de re ipsa quczrere quaU mirari ; 



