Chemical Catechism" was first prepared for the eye of the public; the author having, at the same time, had it in his contemplation to exhibit, in a popular form, a body of incontrovertible evidence of the wisdom and beneficence of the Deity, in the establishment and modification of those laws of matter which are so infinitely and beautifully varied, and whose operation is too minute to be the object of general notice. For, if it could be proved to the satisfaction of youth, that matter is subject to a vast variety of laws which escape common observance, and that, in the adjustment of those laws, the utmost attention, if it may be so expressed, has. been paid to our convonicuce and comfort-such a detail, it was imagined, would tend to make a more indelible impression on the young mind, than the display of the same goodness in the operation of causes which come under our daily notice and observation.

With these views, it naturally occurred to the author, that the work would be very incomplete, should he neglect to offer to the student some of those moral reflections which spontaneously arise in every contemplative mind, when considering the

magnificent system of nature; and though such remarks may perhaps be regarded by some as irrelevant to chemical science, yet, to repeat the former apology, it may be observed, that, in compiling any initiatory book, no writer, as a parent, could lose sight of the necessity of embracing every favourable opportunity of infusing such principles into the youthful mind, as might defend it against immorality, irreligion, and scepticism.

For the accommodation of schools, and to ren der the generality of parents and preceptors more competent to explain and expatiate upon the variety of facts which the science of chemistry presents, and to qualify them in some measure to afford such answers to a number of questions, which the young pupil, in proportion as he advances and becomes more interested in the experiments, will not fail to demand, the author has added a variety of explanatory notes. Many of these will be found to contain new matter, or, at least, what is not generally known or published; others, and perhaps the majority, were drawn from various sources; but as many were quoted from memory, and still more from the common-place book of the compiler, he was obliged, in some instances, either to omit

the authorities, or entirely forego the advantages he had derived from the works, experiments, and opinions of some of the most enlightened chemical philosophers of the age. Here, however, he has constantly been guided by one rule-to produce rather what is useful than original.*

'It may also be remarked, that the catechetical form, which was first chosen for this work, has been found to possess at least all the advantages that any other mode of instructing youth in chemistry can claim, the work having already been introduced with advantage into several of the most eminent seminaries in the kingdom; and, that, if the author's original intention be followed, the progressive improvement of the student will be pleasant, rapid, and correct.

The author assuredly never expected that the answers should be committed to memory verbatim

* With this view, not only a succinct account of the different branches of chemical knowledge has been given, but he has uniformly endeavoured throughout the work to direct the reader to the best treatises in each department of the science, with a view to facilitate higher attainments, and to render "The Chemical Catechism" a kind of text-book for the student.

by the pupil, nor indeed, that the language of the questions should always be literally adhered to by the tutor; but merely that the whole should be clearly comprehended by the parent or tutor, which, with the assistance of the notes, is no difficult task, and then to allow the student to employ his own language to explain his ideas, and form the re

sponses.

Thus, this treatise, it is confidently hoped, possesses every requisite to render it a first book for the chemical student; and that, whether it be employed as a catechism, as a set of dialogues, as matter for familiar conversation, or as a book for the closet, still the original design-a correct initiation into the science of chemistry-will be the result; for if these rudiments of chemical knowledge have been drawn in such a form as to invite the young to study larger and more extended works, and to prepare them to adopt that theory only which can be substantiated by their own experi

ments, the chief intention of the author will then be fully accomplished.

ADVERTISEMENT

ΤΟ

THE SIXTH ENGLISH EDITION.

The author having devoted much time and attention to the improvement of each of the former editions of this work, has now only to add such notes as were nècessary to give the reader a knowledge of those discoveries in the science, which have transpired since the tast edition was published.

A new plate has also been engraved, as a frontispiece for this impression, which, together with fine paper and careful printing, will, he trusts, render THE CHEMICAL CATECHISM, in its Sixth Edition, still more acceptable to the public.

January 18, 1814.