THIS book, the fourth of the series of nine volumes which constitute the “Text-book of Inorganic Chemistry,” edited by Dr. J. Newton Friend, deals with the members of the third group of the Periodic Table. The arrangement of the subject-matter of the treatise in accordance with Mendeléeff's scheme has, no doubt, much to recommend it. The classification, of course, rests upon a rational basis, very different in character from the arbitrary and often inconsistent methods which prevailed prior to the enunciation of the epoch-making generalisation of the distinguished Russian chemist. At the same time, it must be admitted that the arrangement brings together elements which, at first sight, seem to have little or nothing in common. We jump, as it were, from boron to aluminium, from aluminium over scandium and gallium to indium, and thence by way of the “rare earth” metals to thallium. The older systems at least had the merit of attempting to group the elements so as to bring out their natural affinities as manifested by their chemical and physical attributes, and we seemed to pass from the consideration of one element to that of the next by easy and more or less obvious stages rather than by the brusque and staccato method of violent contrasts which appears to follow from the application of the periodic law.
A Text-book of Inorganic Chemistry.
Edited by Dr. J. Newton Friend. Vol iv., Aluminium and its Congeners, including the Rare Earth Metals. By H. F. V. Little. Pp. xx + 485. (London: Charles Griffin and Co., Ltd., 1917.) Price 15s. net.