SECTION VI. 



CHEMISTRY AND ITS APPLICATIONS. 



INTRODUCTION. 



Is our previous pages, we have endeavoured to explain 

 and illustrate those laws which are found to be con- 

 nected with every form and kind of matter. The rela- 

 tions in which the undulatory forces stand are universal, 

 for they do not depend for their action on specific 

 natures, but are rather affections of all bodies which 

 have an existence. Second only to, and yet concomitant 

 with, the forces of gravitation and cohesion, they are 

 uuitly to be found either in a sensible or latent 

 state ; and, as second causes, they produce all the phe- 

 ,.i which we can witness in natural occurrences. 

 nave now to narrow the scope of our ideas. In 

 one i>ense, we have to descend to particulars ; but, at 

 the same time, our opportunities of generalisation will 

 be greatly enlarged. Instead of viewing the entire range 

 of the animal, vegetable, and mineral kingdom, wo shall 

 investigate the nature and properties of the materials 

 of which they are composed. We shall have to inquire 

 into the specific character of the different substances 

 which afford all the variety of appearance and quality 

 observed around us, and to trace, as far as possible, the 

 affinities or attractions which each body has for another 

 availing ourselves of such characteristics to produce 

 what often appear to us as new products. 



It is impossible to overrate the value of Chemistry, 

 either as a branch of natural and experimental philo- 

 sophy, or in its applications to social and commercial 

 purposes. But a few centuries ago, alchemy a con- 

 geries of imposture and deceit was its only representa- 

 tive. The search after the so-called philosopher's stone, 

 which was to turn all the "base" metals into gold, was 

 the only type of chemical science ; and, as in every in- 

 stance in which philosophy is followed simply for its 

 pecuniary reward, tliat and every other recompense 

 eluded the grasp of its devotees. 



In every department of human knowledge, the in- 

 ductive system has been productive of advantage. It 

 checks an exuberance of imagination ; restrains and 

 guides the reasoning powers ; and, in fact, makes the 

 intellect of man of real use to its possessor. The 

 science of Chemistry stands prominently forth as a proof 

 of the truth of this opinion. 



In former days, no theory was considered too crude, to 

 be received, and none so ridiculous as to want believers. 

 Let it only have the sanction of high-sounding names, 

 and its success over the soi-diaant philosopher was 

 certain. If water were raised by a pump, the presumed 

 ni was, that "nature abhorred a vacuum." The 

 process of digestion was considered as the work of an evil 

 but active spirit. Imaginary powers were assigned to 

 sequences and events ; and to sum up .all we can say on 

 the matter, we may state generally, that the causes 

 OBgMtod to account for any effect, were only limited in 

 character and absurdity by the narrow intellect of 

 their inventors. The evil result of this course was not 

 confined to the authors of it ; it spread over the whole 

 of society ; and, as the natural -n;e of supersti- 



tion, it was considered profanity to dispute the dicta of 

 those who assumed to be authorities in such mat- 

 ters. We need scarcely state, that the applications 

 of Chemistry such as it was were of the slightest 



character. When, however, systematic experiment; and 

 rigid induction became the guiding-stars of philosophical 

 research Chemistry, which is, par excelleivx, an experi- 

 mental science, speedily made most rapid progress ; and 

 in the hands of Boyle, Priestley, and Lavoisier, it ap- 

 proached towards a higher and more useful position. It 

 has been no part of our plan, hitherto, to enter into his- 

 torical details ; we shall not, therefore, here commence 

 that course ; but would simply remark, that in our own 

 day, there is scarcely a branch of manufacture, com- 

 merce, agriculture, or, indeed, any occupation, which 

 has not benefited by the application of the truth of 

 Chemistry; and much of our position as a first-rate 

 power in the world at large, is due to the stimulus and 

 aid which our manufactures have derived from chemical 

 Ties. 



In the following pages, we shall first attempt to give 

 our readers an exposition of the general laws of che- 

 mical attraction, and other fundamental principles. We 

 shall then proceed to investigate the chemical history of 

 elementary and compound bodies ; and, subsequently, 

 speak of analysis, and the varied applications of chemical 

 facts to the purposes of manufacture, agriculture, and 

 the like. 



Before entering on this extensive range of inquiry, 

 we must remark, that some considerable knowledge 

 of the subjects which have been treated on in the 

 previous pages will be necessary, if the student desire to 

 make rapid progress ill his chemical studies. All the 

 operations of nature, and those conducted in our 

 laboratories, depend on the exercise of one or more of 

 the agents of Heat, Light, or Electricity ; hence, igno- 

 rance of their laws would entail great embarrassment on 

 those who enter into an experimental examination of 

 chemical phenomena. Independently of this, we need 

 scarcely observe, that a repetition of what wo have already 

 stated, would much encroach on the limits wo have 

 necessarily to assign to each subject, and cause con- 

 siderable confusion. Chemistry calls for but a moderate 

 knowledge of mathematical science ; in fact, scarcely any 

 but the common rules of arithmetic- are involved in its 

 calculations. We have endeavoured to smooth, as far as 

 possible, the various difficulties which may lie in the 

 path of the student ; and, to this end, have given him ex- 

 tended directions for the construction and use of ap- 

 paratus, with a view both to economy and efficiency. Un 

 this head, we would particularly warn all our readers 

 against incurring unnecessary expense, by purchasing a 

 large quantity of apparatus, at the commencement of 

 their chemical course. To the young student, in any 

 branch of knowledge, nothing is so usefid as moderate 

 but surmountable obstacles to his progress. These, 

 whilst checking undue ardour, give him time for re- 

 flection and thought. The attempt to overcome them, 

 induces readiness of resources, and calls out powers which 

 he otherwise would hardly know that he possessed. 

 The experiments suggested are such as may be easily 

 conducted ; and have been introduced so as to give 

 the reader a means of verifying the statements with 

 which they are connected. They are equally suitable 

 for private study, as for exhibition at tho lecture-table. 



