March i6, 1888.] 



SCIENCE. 



13: 



not only the account of the latest development of chemical theories, 

 but also the more important empirical data upon which the theoreti- 

 cal conclusions are based. Of the three parts into which it is 

 divided, the first discusses the atomic and molecular hypotheses, 

 including such topics as the law of Avogadro, Dulong and Petit, 

 and Mitscherlich ; the limitations of these laws, and the causes of 

 observed deviations therefrom; and the periodicity, atomic weights, 

 and properties. The second part, treating of the statics of the 

 atoms, or " the doctrine of the equilibrium of the atoms in their 

 combinations with one another," deals with the forms of combina- 

 tion, the law of atomic linking, and valency, or capacity for saturation. 

 The third part is concerned with the dynamics of the atoms, or 

 "the doctrine of chemical change ;" and under this head is put an 

 account of the connection of mechanical disturbance, heat, light, 

 and electricity, with chemical change, and a discussion of the in- 

 fluence of mass action and of the stability of compounds as depend- 

 ent upon atomic composition and interaction. Careful and cautious 

 weighing of evidence is obvious thoroughout the work ; and while 

 the value of hypotheses, regarded simply as approximations to truth 

 as well as aids to work, is insisted upon, stress is laid upon the 

 need of proceeding with judgment, and of keeping separate, so far 

 as may be, those theoretical considerations which are the abstract 

 expressions of observed facts, from hypothetical assumptions which 

 show an appearance of probability which may or may not be last- 

 ing. To the chemist who wishes to keep up with the tide, a 

 knowledge of the German language, to the point of being able to 

 follow the current of chemical events in Germany, is a matter of 

 necessity, and most chemists are doubtless familiar with the origi- 

 nal of the volume before us ; but, for the student just entering the 

 real work of chemistry, this book seems to us the most important 

 which has appeared in English in many years. 



The Art of Projectio?i. By A. E. DOLBEAR. Boston, Lee & 

 Shepard. 12°. 



This is a new edition of a well-known book, first issued about 

 ten years ago. It has been revised, and contains some important 

 additions, especially a series of experiments on vortex-rings. Pro- 

 jection has come to be so extensively employed, not only as a means 

 of illustration, but often as an aid to research, that many books 

 would be required to describe the uses to which it may be put. 

 Professor Dolbear's book will always be useful as a guide to the 

 tecAnigue of port-lumieres, lanterns, sources of light, etc., and it 

 contains a well-selected series of experiments suitable for presenta- 

 tion by this method. 



The Art of Investing. By a New York broker. New York, Ap- 

 pleton. 16''. 



This is the sort of book that will find many readers ; for although 

 few people, relatively speaking, can invest, yet many more hope to 

 be able to some day, and every one likes to know how it is done. 

 To many its perusal will be like a glimpse through the curtain at a 

 nobleman's ball to a street gamin. It is cleverly written, and puts 

 in a plain, practical sort of way a great many statements that all 

 who invest believe, but few follow. The truth is, that speculation 

 is more or less a disease, and, when it seizes one, it is apt to run its 

 course, cautions and antidotes to the contrary notwithstanding. 

 For this reason a book of this sort is of little value. Many persons 

 who read it will think that they know better than the author what 

 securities are safe, and what are not. Only personal experience and 

 personal loss will convince them. 



Under the head of investing, the author discusses the various 

 investment securities m order, beginning with government bonds. 

 The story of State and municipal repudiation is a sad and dis- 

 graceful one, and in consequence the confidence in a majority of 

 the securities issued by State and municipal authority has long since 

 been shaken. Many readers will be interested in what is said about 

 farm loans, and will applaud the writer's conservative yet fair 

 judgment concerning them. Under the head of speculating, the 

 New York Stock Exchange receives a severe castigation, but one 

 which is thoroughly deserved. It is beyond question that that far- 

 famed institution has done more harm to the legitimate business 

 interests of the country than any other single influence. If people 

 can only be induced to keep away from it a little longer, it will die 



of inanition. Gambling is not very profitable unless some rich out- 

 siders participate in the game. The book will unquestionably be 

 widely read : it is almost too much to expect that it will be widely 

 followed. 



NOTES AND NEWS. 

 Dr. Billings of the Army Medical Museum will signalize the 

 removal to the new building near the National Museum by the 

 preparation of an illustrated catalogue. It will contain drawings- 

 of all the crude and wet specimens of tumors, cancers, gangrenes, 

 etc., and other objects on exhibition in the museum, besides micro- 

 photographs of morbid tissues prepared by Dr. W. M. Gray, the 

 microscopist of the surgeon-general's office. Each picture will be 

 accompanied by a short description of the object illustrated, but 

 there will be no discussion of theories. The work, when completed, 

 will constitute a complete pathology, and will be a most valuable 

 text-book for students and physicians. 



— Prof. C. H. Hitchcock of Dartmouth College has just re- 

 turned from the Indian River region of Florida, where he has been 

 studying the tracks of animals on the sand of the seashore in the 

 hope that they might assist in the interpretation of the fossil foot- 

 marks found in the sandstone of the Connecticut valley in Massa- 

 chusetts. It may be remembered that the late Prof. Edward 

 Hitchcock of Amherst College devoted a great deal of study ta 

 these fossil foot-marks, and published in 1858 a report in which he 

 described, and illustrated by plates, a hundred and nineteen species 

 of insects, worms, moUusca, crustaceans, etc., supposed to have 

 been represented by them. Prof. C. H. Hitchcock is pursuing the 

 same line of study in which his father worked so long, and the re- 

 sult of his recent visit to Florida is that he leans more and more to 

 the opinion that the fossil tracks are chiefly those of crustaceans. 



— The February number of ihe. Journal of the Royal Geographi- 

 cal Society contains an interesting report of William John Steains's- 

 journey to the Rio Doce in Brazil, and its northern tributaries. The 

 traveller, who first went out to South America in connection with a 

 commercial undertaking and the formation of railways, after having 

 accomplished his duties in that direction, undertook the exploration 

 of this river, only the lower part of which was known, although the 

 territory is so near Rio Janeiro. It is principally the difficulty of 

 navigation of the river, which breaks through the coast range in 

 wild rapids and cataracts, and the hostility of the Botocudo, who 

 inhabit this part of the coast, which prevent its being colonized. 

 The country is covered with primeval forest of wonderful beauty 

 and density, and only a few settlements exist on or near the banks 

 of the Rio Doce. Steains's paper is accompanied by a valuable 

 map giving the results of his traverse surveys. A comparison with 

 other maps of the river shows their great inaccuracy. Steains's 

 geographical explorations, which lasted for eight months, were 

 comparatively thorough. He not only explored the main river, but 

 ascended several of its northern tributaries, particularly the Rio 

 Sao Jose, which joins the Rio Doce at Linhares, and several others. 

 By these trips our knowledge of this region is materially increased. 

 On the Rio Pancas he fell in with a sept of the Botocudo, with 

 whom he lived for a month. His observations on this tribe do not 

 contain any new information, and are not so thorough by far as 

 Ehrenreich's study of these tribes, which were mentioned in No. 239 

 of Science. The exploration of the tributaries of the Rio Doce, as 

 well as that of the main river, was made very difficult by the 

 numerous cataracts which had to be passed by long portages. 

 From Steains's paper it would appear as though a considerable 

 amount of private and government surveying was going on in Brazil ;. 

 but very little definite information reaches us so far, and our maps 

 of the greater part of Brazil are still very defective, being founded 

 on very old observations and indefinite reports. From Steains's' 

 paper it does not appear whether his map is based upon astro- 

 nomical observations, or a compass survey. 



— Thomas Gray of the University, Glasgow, Scotland, has ac- 

 cepted the chair of dynamic engineering in the Rose Polytechnic 

 Institute, Terre Haute, Ind., and will begin his work next Septem- 

 ber. Professor Gray is well known in this country for his researches 

 in electricity, seismology, etc., and his work for several years with 

 Sir William Thomson on instruments of precision for electrical 

 measurement. 



