VI ADVERTISEMENT. 



delivered a Lecture upon the subject, at Hazelwood, 

 on the 26th of October last, which was honoured with 

 the attention of a numerous auditory. Upon the de- 

 tails of this lecture the present Memoir is founded. 



The principal object of the following pages, is, to 

 explain, to persons of every class, the objects and the 

 utility of the Physical Sciences of those branches of 

 knowledge, to which the investigation of universal 

 nature has given birth considered as forming a de- 

 partment of Liberal Education. In order to accomplish 

 this intention, I have endeavoured, when entering into 

 detail upon any subject of a scientific nature, to inter- 

 weave, with the technical terms and forms of expression 

 necessarily employed, such explanations and remarks, 

 as appeared requisite, for the purpose, not only of 

 adapting the work for the perusal of those persons 

 who may be unacquainted with the subjects of which 

 it treats, but also of rendering it interesting to them. 

 For this purpose, likewise, I have sometimes disre- 

 garded the precision of scientific nomenclature ; when 

 it seemed probable that a more general mode of ex- 

 pression would render any statement more readily 

 intelligible to the general reader. But I have at- 

 tempted, at the same time, by the introduction of 

 Notes, in which I have examined certain subjects in a 

 more precise manner, and occasionally suggested new 

 views respecting them, to evince, to those readers 

 who may be already proficients in science, that my 

 own views are not wholly incommensurate with the 

 actual state of natural knowledge, and also to claim, 

 in some degree, the character of a cultivator as well as 

 that of a teacher of science. The main object I had in 



