SCIENCE IN MANCHESTER.*
Wilux the indefatigable editors of the Bibliography of Lancashire and Cheshire come to take stock next year of the works issued in those two counties during 1877, the new Treatise on Chemistry will no doubt form the most important item. Manchester may, indeed, be congratulated upon the remarkable series of scientific works which it has recently produced, thanks in a great degree to the possession of such a centre of scientific and literary activity as Owens College. It should not be forgotten, and Professor Roscoe takes due care that we shall not forget, that before the time of Owens College, Manchester had, through the genius of two or three men, been placed in the first rank among English towns. It was there that Dalton laid the foundations of modern chemistry, by his suggestion of the atomic theory. Maintaining himself as a humble teacher in girls' schools, and working, for the most part, with extemporised apparatus, which would excite the ridicule of a modern chemist, Dalton, nevertheless, managed to arrive at a principle which is, and ever will be, the basis of our knowledge of matter. Then, again, the whole of modern physics, summed up, as it is, in the theory of the conservation of energy, rests upon experiments which were first made in an exact and scientific manner by Dr. Joule, of Manchester.
It is most appropriate that a work which will probably be accepted as the leading and standard treatise on its subject should also emanate from that town. It is somewhat surprising, indeed, that it should have been left to Professors Roscoe and Schorlemmer to supply a really good treatise. There are many chemists who, if not equal in original power to those named, might, one would have thought, have devoted themselves to the composition of a treatise which naturally consists, to a great ex- tent, in compilation and literary work. Nevertheless, it is won- derful how few- treatises there are. Graham's chemistry was ex- cellent in its day, but is wholly superseded by the progress of the science. The same fate is rapidly overtaking the late Dr. Miller's Elements of Chemistry. Fownes' book has, indeed, always been an excellent manual, and under the skilful and indefatigable editorship of Dr. Henry Watts, it reappears every now and then in renewed youth. Yet Fownes' manual is a manual rather than a treatise. It serves well for a class of junior students, * A Treatise on Chemistry. By H. E. Roscoe, F.R.S., and C. Sohorlemmer, F.R.S Professors of Chemistry in Owens College, Manchester. Vol. I. The Non-metallic Elements. London: Macmillan. 1877.
but something more was wanted. The works of Professors A. W.
Odling, Armstrong, and others are excellent, each in its own way, but none fill the place of a standard treatise. We think, therefore, that there was plenty of room for this new work. The authors may be congratulated upon the manner in which they have accomplished their task to the extent of the first volume of the treatise, describing the non-metallic elements. Chemical literature tends too much to degenerate into a maze of letters and lines, intended to represent atoms, but conveying no information to the majority of readers. Those who have looked into Pro- fessor Schorlemmer's profound work on the Chemistry of the Carbon Compounds will have a vivid notion of the labour which lies before a reader. In this treatise, however, the authors have diluted the severe theory of the subject with a general description of the discovery, use, and production of every important com- pound of the non-metallic elements. Good accounts are given of the manufacture of coal-gas, and of its analysis. The manufacture of sul- phuric acid, which forms the basis of all chemical operations, is very fully and carefully treated, with the aid of elaborate illustrations, and with the advantage of original information obtained from manu- facturing chemists, both in this country and on the Continent. Under the head of "Phosphorus," we find an interesting account of its poisonous action on the human body, and of the happy results which have followed, in the fabrication of lucifer-matches, from the discovery of amorphous or non-poisonous phosphorus. Then, again, we are glad to find that the authors have throughout paid attention to the history of their science. Chemists have generally been too much inclined to regard everything done in earlier centuries as unworthy of notice. This is better, no doubt, than looking for all wisdom in Aristotle and Galen. But there is a mean between regard for the present and the past. We can never wisely despise a knowledge of the course by which any branch of science has advanced to its present position. We are particularly glad, therefore, to find that in addition to the historical references scattered through the volume, the authors have given a special historical introduction, in which the successive advances towards a correct chemical theory are traced in a brief but interesting manner. Justice is here done to the memory of Robert Boyle, who, it is clear, "was the first to grasp the idea of the distinction between an elementary and a compound body, the latter being a more complicated substance, produced by the union of two or more simple bodies, and differing altogether from these in its properties. He also held that chemical combination consists of an approxima- tion of the smallest particles of matter."
Another distinguishing feature of the present work is the great care which has been bestowed upon the woodcut illustrations. These have been prepared from photographs of apparatus actually in use. Taking the hint, no doubt, from German and French scientific works, the publishers have had the wood-cuts executed in a manner very superior to that customary in England in the case of scientific books. Thus the reader has the advantage of seeing the apparatus represented on the page just as it would appear on the lecture-room table.
Here and there the reader of this treatise will come across important practical remarks. The statement about the use of arsenic in wall-papers deserves attention (p. 541). Arsenic acid, it appears, is being very largely employed in the manufacture of aniline colours, so that it is not only in bright-green papers that poison lurks. We have heard of such serious yet insidious effects arising from the unsuspected presence of arsenic, that we venture to suggest the absolute prohibition of the use of this substance in the manufacture of clothes, furniture, or household decorations. It would surely be better to sacrifice a few of the beautiful new dyes and colouring materials rather than surround ourselves with poison,—and chemists, debarred from the use of arsenic, would soon find satisfactory substitutes.
The remarks on ventilation, again, are interesting (p. 456). We are told that the renewal of air in a room takes place to a considerable extent, even when the doors and windows are shut, by cracks and crevices in doors and windows, end especially through the walls. "Almost instinctively, man appears to have chosen porous building materials, thus permitting, by gaseous diffusion, an exchange of fresh for deteriorated air. The well-known un- healthiness of new and damp houses, as well as of those built of iron, is to a great extent to be attributed to the fact that the walls do not permit a freo diffusion to go on." The authors describe an experiment of Pettenkofer. A plate of iron, furnished with a tube in the centre, is fixed over one side of an ordinary brick or sandstone wall, and a similar plate and tube exactly opposite to it on the other side. A coating of tar round the edges of the plates and the surrounding portions of wall prevents air escaping laterally. It is then found that if air be blown by the mouth into one tube, a puff at once comes out at the other side. If a burning candle be placed at the end
of the exit-tube, it can easily be puffed out, so that the experi- menter may be said to blow a candle out through a stone wall.
If, however, the bricks or stones of the experimental wall be well wetted, it will be found very difficult to blow out the candle as described. It seems, however, that the wall must be well wetted, and even then it is Very difficult, not impos- sible. Moreover, on looking into the details, we find that the experimental wall is only thirteen centimetres, or about five inches thick—that is, we presume, one English brick in thickness —and as nothing is said about plaster and paper, we presume they were absent. The experiment thus seems to fail in supporting the statement of the authors that there is a natural ventilation going on, especially through the walls. There are, we hope, very few houses which have outside walls five inches thick, and whin we consider walls two or three times as thick, carefully plastered on the inside, and then covered with paste and paper, we cannot believe that any appreciable ventilation goes on through such. walls. The unhealthiness of new houses is more probably due to the tightness of the floors, doors, and other woodwork. The in- habitant of a new builder's house becomes painfully aware, after two or three years, that joints before imperceptible begin to gape by the shrinking of the wood. It is through these crevices that ventilation mostly takes place. As the current up the chimney tends to draw air out of the room, air must find its way in to an exactly equal extent. It is thus that we explain the remarkable fact that new chimneys smoke, in the housemaid's opinion. The new chimneys aro correlated with new woodwork, which, when the doors and windows are closed, will not allow an adequate current of air to enter the room, thus preventing a current up the chimney. It is pleasant to reflect that when builders put bad carpentry into their jerry-houses, they really make them airy and wholesome in a manner quite unintended. But we do not believe in ventila- tion through plastered brick walls, and we beg the authors to be a little more careful and explicit on this subject in a new edition. Let them experiment upon their own houses in the meantime.
One feature which distinguishes this treatise on chemistry from those of Graham and Miller is the omission of any introductory account of heat, and other branches of physics intimately con- nected with chemistry. After the historical introduction, the authors proceed to the general principles of the science and the laws of chemical combination. The gaseous liquid and solid states of matter are briefly described. The Kinetic theory of gases is disposed of in a page and a half ; and after a few interest- ing pages on chemical nomenclature, the authors commence at once their description of the non-metallic elements. This course has the advantage of enabling them to devote six hundred pages to the treatment of the elements in question. It is quite obvious, however, that no student could profitably read this work unless he were previously well grounded in the theories of heat and electricity. For this purpose various books are available, such as Professor Balfour Stewart's Elementary Treatise on Heat, Professor Clark Maxwell's Theory of neat, Professor Fleming Jenkins' Electricity, &c. So intimate, however, is the connection between the states of matter and the physical forces, that it admits of question whether a companion volume on chemical physics is not almost necessary. The authors have so far yielded to this view of the matter as to append a small treatise on Crystallography, a science which is certainly not so closely connected with their sub- ject as that of heat. But the errors of the authors are rather those of omission than commission, and it might well be pleaded by them that the science of chemistry is now grown so extensive, that division of labour in absolutely necessary. Regarded as a treatise on the non-metallie elements, there can be no doubt that this volume is incom- parably the most satisfactory one of which we are in possession.
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