802 



8CIENGE. 



[N. S. Vol. XII. No. 308. 



tion in question. For this reason the number 

 of the specimens from which the photograph 

 has been made is given in parentheses usually 

 following the description of the species. These 

 specimens and photographs, then, become of 

 nearly, if not quite, equal value to type speci- 

 mens. 



The purpose of the book is to present the 

 important characters which it is necessary to 

 observe, in an intelligible way ; to present life- 

 size photographic reproductions accompanied 

 by plain and accurate descriptions, so that by 

 careful observation of the plant, and by com- 

 parison with the illustrations and text, even a 

 beginner will be able to add many species to 

 the list of edible ones, where now, perhaps, 

 the collections are confined to the ' pink un- 

 ders.' The number of people in America who 

 interest themselves in the collection of mush- 

 rooms for the table is small compared with those 

 in some European countries. This number, 

 however, is increasing, and if a little more at- 

 tention were given to the observation of these 

 plants and the discrimination of the more com- 

 mon kinds, many persons could add greatly to 

 the variety of foods and relishes with compara- 

 tively no cost. The quest for these plants in 

 the fields and woods would also afford a most 

 delightful and needed recreation to many, and 

 there is no subject in nature more fascinating 

 to engage one's interest and powers of observa- 

 tion. 



In addition to the purposes named above, the 

 book has others. There are many important 

 problems for the student in this group of plants. 

 Many of our species and the names of the 

 plants are still in great confusion, owing to the 

 very careless way in which these plants have 

 usually been preserved, and the meagerness of 

 recorded observations on the characters of the 

 fresh plants, or of the different stages of de- 

 velopment. The study has also an important 

 relation to agriculture and forestry, for there 

 are numerous species which cause decay of 

 valuable timber, or by causing ' heart rot ' en- 

 tail immense losses through the annual decre- 

 tion occurring in standing timber. If the book 

 contributes to the general interest in these 

 plants as objects of nature worthy of observa- 

 tion ; if it succeeds in aiding those who are 



seeking for information of the edible kinds ; 

 and stimulates some students to undertake the 

 advancement of our knowledge of the group 

 which may form a more scientific basis for 

 their arrangement, it will serve the purposes 

 the author had in mind in its preparation. 



Geo. F. Atkinson. 



Engine Tests. By George S. Baertjs, S.B., 



New York, D. van Nostrand Co. 1900. 8vo. 



Illustrated. Pp. 338. 



This work is of a kind always welcomed by 

 the scientific practitioner in engineering ; it is 

 a collection of experimental data gathered to- 

 gether by a well-known and skilled expert of 

 rare experience and, what is still more rare, 

 one who is accustomed to compel every scien- 

 tific device and method to his service in his 

 professional work. Mr. Barrus was one of the 

 first in his profession to make use of the labora- 

 tory and exact scientific methods of determin- 

 ing the quality of steam supplied by the boiler 

 and received at the engine, and to correct the 

 previously always approximate figures for en- 

 gine and boiler efficiency by reference to this 

 datum. He had the exceeding good fortune to 

 be engaged in some of the first and most impor- 

 tant of the scientific studies of engine and boiler 

 efficiency made at the Massachusetts Institute 

 of Technology. He went out into an extensive 

 and varied and fruitful practice as consulting en- 

 gineer for New England steam users and car- 

 ried with him that knowledge of scientific 

 methods and that appreciation of their value 

 which made him a pioneer in the introduction 

 of precise measurements into the practical work 

 of the engineer. His publications represent the 

 outcome of twenty-five years of excellent scien- 

 tific- work. 



In 1891 Mr. Barrus published a volume of 

 selected reports upon steam-boiler efficiencies, 

 and its reception was such as to induce him to 

 publish this volume on steam-engine data. The 

 two volumes probably contain a larger body of 

 recent and exact data of this kind than any 

 similar mass of existing technical literature. 



The introductory portion includes a carefully 

 written account of the methods employed in se- 

 curing the data submitted, as of measuring the 

 feed-water, determining leakage, calibration of 



