xvi SCIENCE PROGRESS. 



bins of the past and found a fresh name for the gnat. Systematic 

 terminology is always a trial to the general zoologist, but whatever 

 terminology is used it should be uniform, and it is a pity to find the 

 same animal posing under two distinct names, as we find the common 

 English earthworm as Lumbricus herculceus and L. agricola, the latter, 

 according to Benham, being a synonym for the former. 



In conclusion, we should like to draw especial attention to the 

 chapters on Distribution, the Philosophy and the History of Zo- 

 ology, a novel and extremely useful addition to a work on zoology. 

 In the comparison of the animals of Britain and New Zealand it is 

 stated that land Planarians are unknown in the former. Although this 

 is generally thought to be the case it is not really so, a land Planarian 

 having been long ago described from England, and more recently from 

 Ireland. It is, however, not to be wondered at that some small errors 

 should creep into a work of this size ; and when we consider the diffi- 

 culties under which these authors laboured, one in New Zealand the 

 other in Sydney, the printers, publishers and artists in England, one 

 can only marvel at the splendid work they have produced, one that will 

 be useful both to the elementary and advanced student alike as well as 

 to the teacher. 



The Outlines of Physics, an Elementary Text-book. By Edward L. 

 Nichols. Pp. 452. New York : The Macmillan Co., 1897. 



In his preface the author says that this book is intended as a short 

 course in physics which should be a fair equivalent for the year of 

 advanced mathematics now required for entrance to many colleges. 

 If this is so, then the " advanced mathematics " must be of a decidedly 

 elementary character, for this book is quite elementary. 



The work belongs to that class which combines the functions of 

 a text-book with those of a laboratory-manual. The chief objection to 

 the book as a text-book is that on account of want of space the author 

 has hardly been able to treat the subject sufficiently fully for even an 

 elementary class. 



The experiments described are in general of such a character that 

 they can be performed without the use of expensive apparatus, and are 

 chosen so that a quantitative result of some kind is to be obtained. In 

 this connection our experience leads us to think that it would have been 

 of much use if the author had devoted a section to the consideration of 

 the method of roughly determining, from the accuracy with which each 

 of the quantities which are actually measured can be determined, the 

 accuracy that can reasonably be expected in the result. The increased 

 importance of the errors made in the measurement of a given quantity 

 if it is involved in the final expression to the second or higher power 

 ought also to be insisted upon, even at the first. 



The author being a fellow-countryman of Rowland it seems strange 

 that the value 772 for the mechanical equivalent of heat is given, al- 

 though it is now known that even Joule's results give, when corrected 

 for errors in his thermometry, a much higher value. 



The figures are on the whole excellent, for they are clear and show 



