22 OCTOBER 1881, Page 23

Inorganic Chemistry. By W. B. Kemshead. (W. Collins, Sons, and

Co.)—This is stated to be an " enlarged, revised, and extended edition" of a book by the same author, published some time ago. As the preface is dated November, 1880, Mr. Kemshead might have taken the necessary pains to have incorporated with his text the most important corrections of old errors and the most important dis- coveries of new truths made up to the summer of 1880. He still, for instance, leaves unaltered the statement (p. 105) that oxygen is a permanent gas, which has never been liquefied. The discovery of the liquefaction of the permanent gases in November, 1877, should have been recorded, notin a supplementary chapter, but in the several places of the text where such gases are described. But three years do not seem to have sufficed for this change. And we do not quite under- stand how this book of Mr. Kemsbead's has been produced. Some parts of it appear to have been printed in a different type and to be of a different date from others, while up to page 97 it is identical with another and smaller work by the same author, going under the same name, but described on its title-page as "20th thousand, re- vised and corrected." In enlarging a small and elementary work so as to make it useful to a more advanced class of students, the mere addition of new materials in the form of supplementary chapters does not commend itself as a satisfactory mode of alteration. But the books before us do not show, so far as we can discover, either a thorough and familiar grasp of the subject on which they treat, or an efficient method of teaching it. They doubtless serve the purpose, and enable pupils who are made to learn their contents to pass the South-Kensington examinations.