WE will not positively assert that no one except Mr. Faraday could have written this book, but we are of opinion that there are very few chemists adequate to such a task, which has manifestly required a considerable share of practical skill, much deep and theoretical knowledge, and no small degree of patience and perseverance, more especially shown in the clearness of the details, and the perspicuous manner in which he has managed to describe prolix and difficult processes. The work moreover fills up a chasm in chemical literature, by embodying almost all that is important relating to chemical manipulation scattered through the writings of others; while the author’s extensive experience has enabled him to correct their faults, and to present the student and operator with many new and important facts and processes, by which the researches of the laboratory are most essentially facilitated.

Such is our general opinion of the treatise before us, and we are persuaded that those who are capable of appreciating its merits will agree in our decision; but it is not so easy to [p276] substantiate our judgment by quotations, in consequence of the general didactic character of the book, and the mutual dependence and connexion of its different parts. We shall attempt, however, to give the general reader an outline of its contents, and point out such parts to the chemist as we conceive particularly useful and worthy attention.

The importance of readiness and dexterity in the performance of experiments has been duly estimated for more than a century. The writings of Black, Cavendish, Priestley, and especially Scheele, as opposed to those of their predecessors, show that they had acquired considerable facility in attaining, by simple and economical means, those ends which had before consumed much time and much expense in their accomplishment: but it is only of late years that the refinements of manipulation have been carried towards perfection; and the researches carried on in the laboratory of the Royal Institution have been not a little conducive to this improvement: to no one, however, is this part of the science more indebted than to Dr. Wollaston, whose skill in what may be called microscopic chemistry is consummate, and who has a host of humble but industrious imitators. So essential, indeed, is the attainment of correct methods of manipulation to the progress of chemical science, that many entire trains of research are exclusively dependent upon it for success. It is true that it must always be subordinate to genius and invention; yet the person who could only devise, without knowing how to perform, would comparatively be able to lend little aid to the extension and usefulness of knowledge: and were it not an invidious task, we might be able to show that some of the greatest discoveries and improvements of the science have originated in dexterity of experiment, rather than in profundity of design. By tact, therefore, in manipulation, a considerable advantage is gained, independent of that resulting from an acquaintance with the principles of the science; and this is so considerable, that, of two persons of equal talent and information in other respects, he who is the best manipulator will soon be in advance of the other; the one will draw just inferences with accuracy and rapidity, while the other will be lost in doubt, and often led into error. Mr. Faraday has pointed out several other cases of prominent advantage, arising from skilful manipulation, especially when very small quantities of matter are to be operated upon, and where accurate conclusions are of more than ordinary importance, as in testing for arsenic and other poisons on judicial occasions. When the substance under examination is rare, [p277] as often happens, the facility of working with small quantities is also of much importance, as otherwise the opportunity of gaining information may be lost, or only retained at great expense. “There existed,” says our author, “in the British Museum a small fragment of a black stone, the source and history of which was unknown: it was unique, no other specimen being in the Museum, or known to be in existence; yet as it presented some peculiar characters, Mr. Hatchett was induced to examine it, and, working with a portion of the stone weighing not more than two hundred grains, he was enabled to discover in it a new metal, which he distinguished, by its various characters, from all those previously known, and which he named Columbium. Ekeberg afterwards discovered a metal, which he named Tantalium, conceiving it to have been observed and distinguished for the first time by himself; but Dr. Wollaston, who examined it, and compared it with columbium, was able to identify it with that metal, although he had not more than five grains of the stone from the British Museum upon which to make his experiments.”

In short, there can be but one opinion respecting the first-rate importance of expertness in manipulation, and neatness, dexterity, and efficacy of experimenting. These are the subjects to which the present volume is directed, and which will, therefore, form a valuable accompaniment to the more general and systematic works. They are discussed under the following general heads:—

The description of a laboratory is followed by two long and well-written sections on the arts of weighing and measuring, in which the account of the methods of determining specific gravities, and of the general management of a delicate balance, are well deserving the student’s attentive perusal: indeed, there are no operations which are more frequently performed in a slovenly and careless manner, than those in which scales and weights are concerned; and we should advise the tyro to sit down with his balance and this book before him, and practise the manipulations which it explains.

The fourth section, on the sources and management of heat, is devoted to the construction and management of different kinds of furnaces, lamps, blowpipes, thermometers, and pyrometers, and abounds in useful hints, and in the details of [p278] practical information; and the same remark applies to the succeeding sections on comminution and solution—indeed, we were surprised at finding so much to be taught in regard to these very simple operations. The seventh, eighth, and ninth sections treat of distillation and sublimation, precipitation, and filtration. Here, and indeed throughout the work, the wood-cuts are particularly distinct and well executed. In the section on crystallization, the uses of that process are enumerated; and to this succeeds an account of evaporation. All these operations are extremely well investigated and described, both as to their principles and as to the most proper means of effecting them; a number of curious circumstances are pointed out, by which their results are influenced, and by which certainty and success may be insured.

The uses of coloured tests are explained and illustrated in the twelfth section. Of coloured liquids the author chiefly recommends the infusion of red cabbage; and as it is not only a very good test for private experiments but of excellent service to the public lecturer in rendering certain changes of composition visible to an audience, it may be worth while extracting the directions for preparing it.

“583. The only substance of the kind, perhaps, worth keeping in solution, is an acid infusion of red cabbage. For its preparation, one or more red cabbages should be cut into strips, and boiling water poured upon the pieces; a little dilute sulphuric acid is to be added, and the whole well stirred: it is then to be covered and kept hot as long as possible, or, if convenient, should be heated nearly to boiling, for an hour or two, in a copper or earthen vessel. The quantity of water to be added at first should be sufficient to cover the cabbage, and the sulphuric acid should be in the proportion of about half an ounce of strong oil of vitriol by measure to each good-sized plant. This being done, the fluid should be separated and drained off, and as much more hot water poured on as will cover the solid residue, adding a very little sulphuric acid. The whole is to be closed up, and suffered to stand until cold, and then the liquid poured off and added to the former infusion. The cabbage may now be thrown away. The infusion is to be evaporated to one half or one third its first bulk, poured into a jar, allowed to settle, and the clear red fluid decanted and preserved in bottles. The residue may have water added to it, the solid part be allowed to subside, the clear liquor drawn off, evaporated and added to the former, or it may be dismissed altogether. This solution will keep for a year. When [p279] required for use, the acid of a small portion of it should be neutralized by caustic potash, or soda, (not by ammonia,) when it will assume an intensely deep blue colour, and will, in most cases, require dilution with twelve or fourteen parts of water. The red liquor of pickle cabbage will, occasionally, answer the uses of the solution, and is, when required for service, to be neutralized in a similar manner.”

For test-papers, litmus and turmeric are the most essential, and several precautions in preparing and using them are here pointed out, which, though apparently trivial, are, in fact, extremely important in insuring correct conclusions. We transcribe a part of the account of the applications of these coloured papers, as a specimen of the clear minuteness with which the details of the work are given, and as a sample of the author’s general method and style, where subjects of much greater intricacy are to be explained.