volume too unwieldy and expensive for the use of those who, in most cases, never even read but a small portion of its contents. In these remarks, we are far from undervaluing the many very excellent treatises so well known both here and in England. We wish merely to show their inadequacy to a particular object.

On the other hand, the striking character of many phenomena, attracting the attention of the most ignorant, has led to what are called popular courses of chemistry, in one, two or three lectures, illustrated by brilliant experiments. In these, the brilliancy of the combustions and the noise of the explosions are by many considered the grand criteria of merit. Lectures of this kind have given rise to numerous treatises of a character neither scientific nor even correct. Between these extremes, of too great prolixity and too much superficiality, it is not easy to point out the proper mean. We regard the work whose title stands first at the head of our paper as a most valuable text-book, and fulfilling those conditions which we have proposed as necessary. The course of Columbia college directs the study of chemistry during the Sophomore year, while in most other institutions this subject is reserved for the Junior or even Senior year, and for this reason a still greater simplicity of style is found necessary.

We propose, in the first place, to examine certain features of this work which are novel and useful at the commencement, the student does not find himself disheartened by a formidable array of abstract propositions and theoretical considerations, for a correct understanding of which a pretty extensive knowledge of chemical facts is necessary. The earlier pages are devoted to a succinct exposition of the principles of heat, electricity, magnetism and light, in so far as they are absolutely necessary to the study of elementary chemistry. Next follows a description of the various applications of heat in chemical processes, illustrated by cuts of some of the most approved of modern apparatus. The pupil, thus prepared, enters upon the consideration of atmospheric air, after the study of the mechanical properties of which, its analysis is introduced and explained. Its constituents are then taken up and treated of at length, together with some of their most important combinations with each other. This method combines the advantages of the analytic system, together with the benefit of the most familiar objects of investigation. Four elements of commonest occurrence are thus

almost imperceptibly studied. The doctrines of definite proportion and chemical affinity are not yet broached. The facts relating to them are simply announced as they occur in their proper place.

The next division treats of the remaining non-metallic elements or metalloids, together with their compounds; and in the description of the latter, their composition is always numerically considered. At this stage of the study, so many facts have already been brought forward and explained, that no difficulty will be found in comprehending the fourth division, which embraces the subjects of chemical affinity, definite proportions, combustion, etc. In fact, the preceding pages are so carefully arranged as to prove a true induction to these doctrines, a mode of proceeding directly the reverse of the common one, which, in explaining them at the outset, is obliged to pre-suppose nearly all that follows. There are many points in this part of the work which are peculiarly happy and likewise original.

The fifth division is devoted to the metals. The sixth, to the salts. In this portion of the treatise will be found a store of really useful information, possessing that grand qualification so often lost sight of when the attempt to impart practical information is made exactness. The sixth concludes with organic chemistry and a neat exposition of the general principles of analysis.

Throughout the work, we find abundant illustrations of all the apparatus employed. The advantages of this plan are great, for the student is not only better able to comprehend the experiments, but also provided with the means of obtaining substitutes for more costly implements in his own investigations. It is now well understood that, however appropriate or even necessary for class illustration the more delicate and costly apparatus may be, for the purpose of individual satisfaction a few cheap articles are all-sufficient. Thus, with a gun-barrel, a few tobacco-pipes, some glass tubes, vials, wine-glasses, and even fragments of glass, many an industrious student has not only been able to repeat the experiments of others, but even to venture upon original research. To such, this little work is a real treasure, and for this reason no more suitable treatise on chemistry could have been furnished by the enterprising publishers of the District School Library.

We have dwelt upon the peculiarities of the work, rather for the sake of indicating its original character, than for any testimony we might bear to its value. A sufficient commendation is to be found in the fact, that its character is the result of the valuable experience of Professor Renwick, derived from many years spent in studying and lecturing upon the

science.

After the beautiful vindication of the study of chemistry by Sir Humphrey Davy, in his "Consolations in Travel,” it would be considered needless to enlarge upon that subject. Not only are most of the arts, even those commonly considered as mechanical, intimately connected with chemistry, but most of our domestic operations are dependent upon the principles of the same science. In our young country, there are very many additional inducements to this study, and this is abundantly evident from the immense development of our mineral resources dependent upon recent scientific examinations. It is also to be borne in mind that many of the rarer metals, whose use in the arts is only limited by their scarcity, are likely to prove more abundant in various parts of the United States than in other localities, and thus a wide field. is spread before the youthful chemist.

But whatever may be the utility of this study, there are higher and better reasons for instructing youth in chemical science. The claims of any branch of the history of nature are not to be disregarded, although its immediate bearing upon the business of life may not be a sufficient answer to the cui bono of the captious utilitarian. What lesson can be more impressive than that which teaches us the wonderful and sometimes mysterious laws which display the admirable adaptation of all things to those ends which none but infinite wisdom could have foreseen? To be enabled to entertain truths as wonderful and incomprehensible as they are real and incontrovertible, is to be prepared for the reception of those truths which, though farther beyond the capacity of finite minds, are more closely related to their everlasting welfare.

Regarded in this light, no study can be more appropriate to the training of the youthful mind than that of chemistry; and while we avoid those details and minutia which would disgust the beginner, we must present to him a real science, not a crude and unconnected recital of facts and experiments. That this scientific character, without the sacrifice

of simplicity, belongs to the work before us, will be evident both to the teacher and the pupil.

The claims of the ancients to scientific knowledge have often been discussed; yet the rare combination of classical attainments and scientific knowledge having scarce ever been brought to bear upon the question, we may as yet consider its solution incomplete. It is very certain that, while many have given to them an undue credit for what we now call science, others have gone to the opposite extreme and grossly misrepresented many of their opinions which were really more philosophical than we generally allow. It is thought by some that these erroneous estimates are derived rather from the mistranslations of Aristotle during the dark ages, than from any foundation for them in the original. For instance, it is contended by some that the four clements, fire, air, water, and earth, were rather the four states in which matter is found, in combustion, in the form of gas, liquid, and solid.

Were we allowed to hazard a conjecture, we should say that the knowledge of the ancients embraced a multitude of facts, (far greater than is commonly supposed,) but no real arrangement or science, properly so called. They drew from an immense magazine of recipes, but they had no index or catalogue to facilitate their reference.

Of the infancy of chemistry we know but little. Taking its origin from the forge, the apothecary, the pottery, and the shops of other artisans, it became obscured in the hands of the alchemists, and did not emerge until within comparatively few years. Its history furnishes some admirable passages; and yet, except to those devoted to the science itself, but little is known of many of the most remarkable men who have ever lived. The fact that the profound chemist must present the rare combination of scholar and workman, would at once point out a class of men of entirely different cast of mind from mere abstract philosophers, and likely to afford a host of amusing and instructive biographies.

We know of no writer who has turned these advantages to better account than Dumas, in his "Leçons sur la Philosophie Chimique." These lectures were delivered in 1836, and with the profoundest views of chemical theories, contain some of the most spirited and amusing sketches of character that ever came from the lively pen of a Frenchman. Unfortunately for the English reader, this work is only known in

the original; and even of that, it would seem that but few copies have left France.

Did our limits permit, we would present to our readers some of our author's animated sketches of the older chemists, from Roger Bacon and Albertus Magnus to Stahl and Rouelle; but we must content ourselves with a single extract from this part of his work, which gives an admirable summary of the views of the alchemists, and then pass to a more recent era in the history of the science. The summary is as follows:

"During the long period the history of which we have reviewed, fire was regarded as a universal agent. Its power was represented as unlimited. Nothing could be accomplished without it; by its means, all things were possible. It compassed the transmutation of metals. In our own times, we have had an analogous case in the exaggerated agency of electricity, by which every thing is explained. Well, a similar exaggeration of the power of fire misled the alchemists. They had remarked that by the aid of fire minerals were reduced from the earthy to the metallic state. They imagined that the earths attained a sort of perfection, which encouraged them to hope still farther. They concluded that, by skilful management, fire might bring the common metals to a still higher degree of perfection. Hence, their idea of the conversion of silver into gold."

"A long series of experiments, numberless and painful efforts unattended with success, and striking instances of the sad condition to which their deplorable madness led, were necessary to convert them from notions so deeply rooted. The alchemists, amidst all their illusions, at the time of their meridian and in their decline, have always rendered service to chemistry by publishing, without concealment or prevarication, all those observations which appeared to them irrelevant to the constant object of their labors. On the other hand, they reserved with jealous care, and concealed in a thousand ways, all those operations which had reference to their grand ultimatum. But they reserved nothing else. Strange prejudice which led them to despise truth and worship error! Strange division of knowledge, by which they appropriated false, injurious and dangerous doctrines, hiding them under a bushel, and scattered with a lavish hand and without regret those principles which were true and necessary for the progress of humanity!"

The history of ancient chemistry finishes with Stahl, who died in 1734. From his time, no new discoveries of importance were made in the science until about thirty years after, when we find three individuals figuring in the history of