KEMP'S PIEASIS OF MATTEL*

Tins " outline of the discoveries and applications of modern che- mistry" is less intended for the student of chemistry than "for the wants of the general scholar and of men of the world." The arts of life, from agriculture and horticulture, through the entire range of our manufactures, even coming home to domestic comfort and health, are so closely connected with chemistry, that some knowledge of it is indispensable to the successful exercise of many callings, or even to understand the rationale of the various artifi- cial processes that are continually going on about us. Besides the inextricable connexion of chemistry with civilized life, the wonders it exhibits in nature are of a kind to excite the atten- tion and reward the application of a liberal curiosity. A book, therefore, is a desideratum, which should present the principles and leading details of inorganic and vital chemistry in relation to animals, vegetables, and the operations of the laboratory, as well as the grander operations of nature in the workings of the world— that is, geology past and present.

This is done very well by Dr. Kemp in the volumes before us. In a subject so vast in itself, and trenching on the one hand upon natural philosophy and upon vegetable and animal physiology on the other, objections may be raised to any plan. According to a person's preconceived ideas, something will be treated too curtly, something too fully ; and we think that geological and animal chemistry might both have properly admitted of extension. Ex- ceptions might also be taken to other parts ; but upon the whole the book fulfils its purpose. The arrangement is well planned ; the exposition of general principles is broad, clear, and sometimes eloquent ; the particular explanations are plain and neatly illus- trated ; the experiments are conclusive in their proof and easy to imitate. The Phasis of Matter will be found a useful and rather elegant introduction to the study of the science, as well as a broad and interesting survey of the operations of inorganic and organic

* The Phasis of Matter ; being an Outline of the Discoveries and Applications of Modern Chemistry. By T. Lindley Kemp, M.D. In two volumes. Published by Longman and Co.

chemistry, to those who are disposed to rest satisfied with " gene- ral" knowledge. Including an elaborate appendix, the volumes consist of five parts. The first embraces the leading outlines of chemistry, so far as is necessary to be known in order to proceed to the study of the existing "elements" and the more important bodies formed from them. And this part is continually illustrated by experiments. The second book treats of the crust of the earth, or the chemistry of geology ; handling the composition of the most important of the minerals, the chemistry of the rocks, and the history of British geological formations. Book the third is occupied with organic chemistry, almost limited to vegetation. Probably from its re. lation to agriculture, this branch of the subject is pursued at great length, forming one of the most complete and practically useful sections of the work. The fourth briefly handles the ge- neral laws of animal life, including a consideration of the sap and the blood, and their circulations. The fifth part, though printed as an appendix, extends to greater length than either the che- mistry of geology or of life, though particular subjects are briefly treated. It contains the application of chemistry to the arts; and deals with thirteen subjects, from rural economy, soapmaking, and the culinary art, up to medicine.

It will of course be inferred that The Phasic of Matter makes no claim to original discovery. Its first merit is its conception— the idea of considering chemistry in so great an extent, as well in its laws as in their application. Closely connected with this merit is the object that the work aims at fulfilling—to furnish a me- dium between a technical or professional treatise and the popular compendium. There are, however, several treatises on the ele- ments of chemistry, so good that the present work is more remark- able for its tone and style than for any positive scientific supe- riority. This more elevated and as it were man-of-the-world tone, combined with considerable ease of exposition, is the remarkable feature of the execution, apart from mere literary qualities.

The question of creation by direct interference, or of laws ori- ginally impressed upon matter, latent in the absence of exciting conditions, active when the necessary conditions are present, has been noticed lately by the Reverend Baden Powell, with a leaning to progression through impressed laws. The subject is one that will be more mooted the further that nature is investigated. In fact, but for the plentifulness of the examples around us, we might say that creation is continually going on. The laws of chemical affinity —the results which follow mixing bodies—might seem as remark- able in the production of properties as the origin of the lower class of life, but for our familiarity with them.

• " Great changes usually accompany these chemical actions in which af- finities are brought into play. In general, the substances that combine lose their properties, and the new substance that is formed acquires properties peculiar to itself. There is, for instance, sulphuric acid and potassa, both being very caustic substances. The acid, moreover, is very sour to the taste, and reddens any vegetable blue colour, while the potassa has a very alkaline taste, and :makes any vegetable blue that it comes in contact with green. Yet these two substances unite together and form sulphate of potassa, or sal polychrest, as it used to be sometimes called ; which is not caustic, has a bitter taste, and if brought into contact with vegetable blues does not affect them at all.

" There is also very often a change in density, and two bodies that com- bine together rarely occupy the same space that their constituents did before they did so combine. Generally speaking, the bulk of the new body is less than the united bulk of the combining substances. The colour, too, is very often affected. Thus, if we combine white mercury and yellow sulphur to- gether, we obtain the bright red compound named vermilion. Iodine has a

violet hue, and lead a bluish colour, but the compound formed by these is of a bright yellow colour. Oxide of copper is brown, but most of its salts are either green or blue-white ; on the other hand, the salts formed by the yel- low oxide of lead are generally colourless. " A change of temperature, also, often accompanies chemical action. When two substances combine together and occupy less space than they did, of course heat is evolved. So also is it if a gas become liquid, or a liquid solid. If the reverse of this take place, as before explained, then cold is given out. When we come to consider the phenomena of combustion, we shall have occasion to notice another manner in which chemical action causes an evolution of heat.

" Another very common change that goes along with chemical action is alteration of form. Solids become liquid, liquids solids, and both sometimes gaseous. The decomposition of gunpowder by heat is a common example of a solid becoming gaseous."

Here is a fact or conjecture in reference to the composition of other worlds.

" NATIVE EON.

" Small portions of native iron have occasionally been found, but we here notice it for the sake of mentioning meteoric iron, which is very interesting, inasmuch as it would seem to indicate that, in some respects at least, the chemical composition of the moon resembles that of our globe. For a long time it has been an object of popular belief that stones fell from the air upon the earth, and one of these stones was worshiped for long in a Syrian tem- ple. But it is only within the last century that the evidence regarding them has become so strong that scientific men have recognized their existence. Many have fallen at many different parts of the world ; but when analyzed they all agree in affording a large quantity (about ninety per cent) of native iron, and some of the very rare metal nickel, with varying traces of sulphur, cokalt, &c.

" The most probable origin of these meteoric stones is, that they have been ejected with such force from some of the many volcanoes that exist in the moon, that they have fallen out of the attraction of that satellite into that of our planet."

The steady action of natural law in opposition to human sense of right seems in nothing more remarkable than in the distribution of fame. Qualities energetically and even successfully exercised do not insure it. "Brave men were living before Agamemnon," and are unknown for want of a poet. Yet even the poet himself must depend upon his age and country for the advantageous exercise of his faculties. The discoverer is in the same plight; he may fall upon an age too soon, and his unavoidable errors prepare the way for the greatness of another. In agricultural chemistry, Van Helmont, Tull, Wallerins, and Mr. Grisenthwaite of Nottingham, laboured for Liebig to reap the glor.

"The first step in the right direction although it led to results altogether erroneous) was probably made by Van elmont. He was struck with the fact, which indeed every man who ever thought must have been struck with, how is it that an acorn, for example, which does not weigh more than a few grains, becomes converted into a large oak that turns the balance against many hundredweights ? All that matter which forms these hundredweights of timber and bark must have been derived from somewhere. Van Helmont endeavoured to decide the question experimentally ; and chose the willow to experiment upon. He came to the conclusion that the growing plant de- rives its nutrition, i. e. its structure, from water, and that water is by some physiological process converted into stem, leaves, bark, seed, &c. In his day the constitution of water was not known, and there was nothing absurd in his conclusions. But now we know that they were altogether incorrect ; for water, when pure, only contains oxygen and hydrogen, and the willow contains, besides these elements, carbon, nitrogen, phosphorus, and several others. Van Helmont was deceived because he used impure water that ac- cidentally contained these other ingredients.

"The presence of soil, however, was so evidently necessary for vegetation, and crops grew so much better upon some soils than others, that it became impossible not to believe that the earth in which plants grew had something to do with their structure. Tull, at the beginning of the last century, made a very near approach to the discovery of the truth. He came to the oonolu- sion that the food of plants consisted of water along with earth, and that this water and earth was converted into their structure, and constituted the material bulk to which they attained. The actual chemical constitution of the soil was quite unknown in Tull's time, and be not unnaturally assumed that the earth was taken in by the roots of a plant only when in a state of fine powder, and he inferred that fertility in a soil depended upon obtaining this state of comminution, and that a soil could be rendered and made to remain fertile by continually reducing it by mechanical means to a powder. He tried the theory experimentally upon his own farm. From a peculiarity in his soil his plan succeeded at first, but very soon hie land became sterile, and hq was ruined. Both earth and water were clear) necessary for plants, but not exactly in the manner that Tull thought. Nevertheless, he was so near the truth, that the practical mode of tilling the soil that he introduced, deep ploughing and drill husbandry, are still regarded as indispensable to all good farming. "Two of the ancient elements had been supposed to furnish the food of plants, and then Waller, or Wallerius, professor of mineralogy at Upside, about a century ago, in his Elements of Physical and Chemical Agricul- ture,' maintained that the atmosphere was the main source of the food of plants, and that the air contained all the materials and constituent principles of vegetables; and, which is a most remarkable circumstance, he ascribes, as one cause of the nutritive property of the air, the presence in it of volatile alkalies in a state of vapour. • • •

"It was an Englisman, Mr. Grisenthwaite, of Nottingham, who first clearly perceived the relation between the mineral matter of the Boil and that of plants which grew upon it. He first published his discovery in 1818, and still more fully in 1830. As the admirers of Liebig have claimed for that distinguished chemist the discovery, it is proper to quote some of the passages from Mr. Grisenthwaite's 'New Theory of Agriculture.' Let us recur once more to the grain of wheat. In that grain there always exists, as has been stated, a portion of phosphate of lime. It is the constancy of its presence that proves beyond all reasonable doubt that it answers some important pur- pose in the economy of the seed. It is never found in the straw of the plant ; it does not exist in barley, or oats, or peas, although grown upon the same ground and under the same circumstances; but, as has just been ob- served, always in wheat. Now, to regard this unvarying discrimination as accidental, or to consider it useless, is to set at defiance the soundest principles of reasoning that philosophy ever bruited.' "

The importance of the conclusion seems to justify a verbal remark upon the title. " Phasis," in English, merely means ap- pearance. The changes even of inorganic chemistry go further than a phase. It is held that matter is essentially atomic. In a certain loose sense its outward form may be said to be only changes of appearance ; but these changes, at least as regards chemistry, are followed by change of properties. Phasis, therefore, is not only a strange term, but it very insufficiently indicates the nature of the book. In etymology " transformations " would not meet the diffi- culty, in usage it would.