ERRATA. Page 18. line 23., for "solution" read "portion." 23. line 12. from bottom, for "NH3-Cl" read " NH2HCI." 32. line 20., for " Oxone" read " Özone.” 47. line 12. from bottom, for "yvoμai" read "yelvoμal.” 61. line 2., erase "à." 136. line 13., for "homomorphous " read " " isomorphous." GOVERNMENT EXPERIMENTS ON FEEDING GATTLE. Just published, in fcp. 8vo. price 5s. cloth, EXPERIMENTAL FOOD of ANIMALS and the FATTENING of CATTLE: with Remarks on the Food of Man. Ry ROBERT DUNDAS THOMSON, M.D., of the University of Glasgow. A very elaborate and useful work on the subject of which it treats." Bell's Messenger. "The question of the origin of the fat of animals appears to be completely resolved by these beautiful and elaborate experiments.' - Baron Liebig. "In this little work we have a very explicit and intelligible account of a long series of experiments made at the instance of the Government, together with some general principles of great practical importance deduced from them by the author." Spectator. "We would direct the attention of our readers to this little work, not merely as it contains a full report of the experiments already referred to in our pages, which its author undertook on malt, barley, and other substances, as food for cattle, but also as it contains a general view of the subjects of food and digestion, which it is of the greatest importance for farmers to be acquainted with."-Gardeners' Chronicle. LONDON LONGMAN, BROWN, GREEN, & LONGMANS. INTRODUCTION TO THE RUDIMENTS OF CHEMISTRY. INTRODUCTION. THE material world, or all that we see around us, consists, according to our present knowledge, of sixty-two different kinds or species of matter, termed elements. The particles of which each species or element is composed are supposed to be hard round bodies, or atoms which cannot be divided or broken. The same kinds of particles have a tendency to adhere to each other, by what is termed the attraction of cohesion; thus sugar not only exists in the state of powder, but in lumps, masses, or crystals. But besides this aggregation, one species of particles has an affinity for another kind; as when iron is exposed to moist air it becomes covered with rust, in consequence of the union of the particles of the oxygen of the air with the particles of the iron by the power of chemical affinity. Now, chemistry may be defined generally to be that science which teaches the characters of the sixty-two forms of matter, and their action upon each other. The result of this action is an infinite variety of chemical compounds, as oxides, acids, salts, neutral bodies, &c. The particles or atoms of each kind of matter do not alter in weight or size, but are invariably the same; so that a definite or combining weight is attached to them, which is termed the atomic or equivalent weight. Thus the weight of the atom or ultimate particle of iron is 3y, and that of sulphur 2. When these bodies unite, they form 5} sulphuret of iron (FeS). But they can also unite in another proportion, viz., one atom or particle of iron with two particles or atoms of sulphur; they then form the bisulphuret of iron (FeS2), the compound particle or atom of which weighs 7. Chemical bodies, both simple and compound, are either amorphous (privative a and uoppn, shape, destitute of shape), B |