July 11, 1884.] 



SCIENCE. 



39 



frequenting the same stream, may simply con- 

 gregate about some bubbling spring, that, issu- 

 ing from the bed of the pond or creek, tempers 

 the surrounding waters, and renders it hab- 

 itable during the severest weather. This, it 

 seems to me, is a marked instance of the ex- 

 ercise of choice on the part of fishes, and has 

 an important bearing on the question of their 

 intelligence ; and it is, furthermore, corrobora- 

 tive of the statement, made at the commence- 

 ment of our former article, that hibernation is a 

 faculty which many animals possess, the exer- 

 cise of which is largely, if not wholly, optional. 

 Charles C. Abbott, M.D. 



TAIT'S HEAT. 



Heat. By P. G. Tait. London, Macmillan, 1884. 

 368 p. 8°. 



The author says in his preface, " Clerk Max- 

 well's work is on the theory of heat, and is 

 specially fitted for the study ; that of Stewart 

 is rather for the physical laboratory : so that 

 there still remains an opening for a work 

 suited to the lecture-room." 



The book before us is the best text-book 

 for a student who is beginning the study of 

 heat that we have seen. The author begins 

 by giving the reader a good idea of force and 

 energy, of the nature of heat, and of the dif- 

 ference between heat and temperature. Heat 

 is a form of energy : temperature must at first 

 be looked on "as a mere condition which de- 

 termines which of two bodies, put in contact, 

 shall part with heat to the other." 



We do not, however, think that a student can 

 get a clear idea of the second law of thermo- 

 dynamics, and of absolute temperature, from 

 the brief sketch given in chap. iv. In order to 

 have confidence in the deductions from Carnot's 

 cycle, a much more thorough study of thermo- 

 dynamics is necessary. Chap, xi., on thermo- 

 electricity, contains a very good account of the 

 theoiy and of the experimental part of the sub- 

 ject. -The results of Tait's experiments upon 

 the form of the thermo-electric lines at high 

 temperatures are given, and also a table of the 

 calculated specific heats of electricity for many 

 metals. 



The chapter upon combination and dissocia- 

 tion, showing the application of the two laws 

 of thermo-dynamics to chemical combination, 

 is valuable, as such a discussion is not often 

 to be found in text-books. 



This book is not everywhere eas}^ reading. 

 Though by far the greater part can be under- 

 stood by a student who has no knowledge of 



differential calculus, yet there are certain parts 

 — as in the application of Fourier's method to 

 determine the temperature of the earth's crust, 

 and in chap, xxi., on the elements of thermo- 

 dynamics — where a knowledge of calculus is 

 necessary. 



MERRIMAN'S METHOD OF LEAST 

 SQUARES. 



A text-book on the method of least squares. By Mans- 

 field Merriman. New York, Wiley, 1884. 

 8+194 p. 8°. 



This author published his Elements of the 

 method of least squares in 1877. It was favor- 

 ably received ; and, the edition having been 

 exhausted, the work has been now recast, and 

 republished under the above title. In the ori- 

 ginal work the author attempted, in the first 

 part, to explain the method, and its application 

 to the combination of observations, and, in 

 the second part, to establish analytically the 

 mathematical principles of the subject. In the 

 present work the principles are first developed, 

 and the applications follow : this order of ar- 

 rangement must, on the whole, be better than 

 the other. The endeavor to have the reader 

 become practically acquainted with the subject 

 before he makes any extended analytical study 

 of it, may possibly enable the student who is 

 somewhat deficient in his mathematical train- 

 ing to obtain a command of the method when 

 otherwise it would be beyond his reach ; but it 

 does not seem worth while to assume that those 

 who are to use this method are such poor 

 mathematicians that the work should be modi- 

 fied in this way for their benefit. The author 

 has done well in this new work in making a 

 straightforward, logical development of the 

 method and its applications. In a cursory 

 examination of the work, it does not appear 

 that the author has, in general, enlarged the 

 book by materially adding to the theoretical 

 part, which was already sufficient for the pur- 

 poses in view. The additions are found in the 

 practical portion of the work, and are of a 

 nature to considerably enhance its value to the 

 civil engineer, for whom the book is primarily 

 intended . 



It has seemed to the writer that the introduc- 

 tory chapter, which treats of the general prin- 

 ciples of probability, might have been enlarged 

 to advantage, or at least that the reader should 

 have been referred to some good source of in- 

 formation, such as the excellent little book of 

 Whitworth on choice and chance ; as this is a 

 subject respecting which he probably has little 

 or no previous knowledge. Taken as a whole, 



