Geology and Natural History. 335 



7. Le<jons sur les Metaux. Par Alfred Ditte. Second 

 Fascicule, 4to, pp. 64, 667. Pari;?, 1891. (Vve Ch. Dutiod.)— We 

 have already noticed the first part of this excellent and exhaustive 

 work. The second part sustains fully the high standard of excel- 

 lence previously attained. It begins with magnesium, zinc and 

 cadmium, then treats of the iron group of metals, and of alumi- 

 num, then considers the rare elements of the cerium and yttrium 

 groups, then antimony, tin, bismuth, tungsten, molybdenum, vana- 

 dium, silver, lead, mercury, copper, gold and the platinum group. 

 As iu the earlier part the thermochemical relations are given in 

 each equation and the reactions of formation of compounds are 

 well developed. g. p. b. 



8. Solutions by W. Ostwald, Leipzig ; being the Fourth Book 

 with some additions of the second edition of Ostwald's Lehrbuch 

 der allgemeinen Chemie. Translated by M. M. Pattison Muir, 

 Cambridge. 316 pp. 8vo. London and New York, 1891 (Long- 

 mans, Green & Co.) The subject of solutions is at once one of 

 the most interesting and difficult of those which belong in com- 

 mon to Physics and Chemistry. It is one, moreover, in which 

 very rapid progress has been made of recent years largely as 

 based upon the theory of solutions founded by van't Hoff. The 

 presentation of the whole subject in its modern form is hence 

 a great service to English-speaking students and this work 

 must receive from them a warm welcome. As stated above, the 

 volume is a translation of part of the last edition (1890) of Ost- 

 wald's great work on Chemistry, and has gained greater unity 

 and completeness from the able work of the English editor as 

 well as through the revision by the author. 



II. G-eoloGy and Natural History. 



1. Ueber Tertiarpflanzen von Chile / von H. Engelhardt. 

 Abhandlungeu der Senckenbergischen naturforschenden Gesell- 

 schaft, Band xvi, Frankfurt a. M., 1891, S. 629-692, pi. i-xiv. 

 — This memoir, announced a year earlier in Isis, describes the 

 fossil plants collected by Dr. Ochsenius chiefly at Coronel and 

 Lota in the province of Concepcion on the bay of Arauco, west 

 coast of Chili, a few from Punta Arenas in the Straits of Magel- 

 lan. The deposits are of Tertiary age, believed by the author to 

 be Lower Miocene (Oligocene) or possibly Upper Eocene. One 

 hundred and one species are distinguished, only one of which, 

 Chondrites subsimplex Lx. 5 from the Laramie of Raton mountain, 

 New Mexico, was previously known. There are four ferns, one 

 cycad, two palms, one conifer (Sequoia), one unnamed species of 

 Ephedra, and two fruits (Carpolites); the rest are all dicotyledons 

 and consist of leaf impressions only, many of which, however, are 

 well preserved. In determining these latter the author has been 

 guided by the hypothesis that they ought to represent the ances- 

 tors of now living South American forms, and has referred the 

 gi-eater part of them to genera inhabiting that continent, chiefly 



