242 Notices respecting New Books. 



of those peaceful days when a man could sit down to a book 

 quietly, read it carefully, and thoroughly digest its contents. The 

 rush and hurry of modern life have altered all that. The days 

 when knowledge was so limited that a single individual could 

 master the whole of physical science have long gone by ; and one 

 of the great difficulties confronting every worker in science 

 nowadays is that of keeping pace with the resistless tide of modern 

 investigation in only one particular department. The onward 

 sweep of discovery and invention imposes a burden on every 

 specialist which, however fascinating his subject may be, is at 

 times very heavy ; and every effort to lighten it must be gratefully 

 welcomed. Most of our scientific societies have already done a 

 great deal towards that object, by publishing abstracts of all the 

 more important papers appearing in contemporary journals. Not 

 less important than this is another method of bringing within easy 

 reach of the student the work of our leading men of science — that 

 of publishing their collected papers. It would be difficult to over- 

 estimate the saving in time and trouble which this method effects. 

 Formerly, this was a task which was but seldom undertaken by 

 the author himself, and was generally left to the loving care 

 of his friends. It seems to us much more satisfactory that 

 the author should be his own editor, and this practice has, 

 fortunately, become quite common in our time. The names of 

 Kelvin, Stokes, Heaviside, and Tait will occur to everybody as 

 affording instances of this mode of procedure. And to these may 

 now be added that of Osborne Eeynolds. 



A truly monumental work is this second volume of Papers, 

 which covers the period 1881-1900 of the author's scientific 

 activity. Many of the papers mark an epoch in the advance of 

 knowledge. Although dealing with a large variety of subjects, the 

 papers of greatest importance are those which are concerned with 

 the motion of fluids — a subject which Professor Osborne Reynolds 

 has made peculiarly his own. Of these, the most important are 

 the following : " An Experimental Investigation of the circum- 

 stances which determine whether the Motion of Water shall be 

 direct or sinuous, and of the Law of Resistance in Parallel 

 Channels" [originally published in 1883 in the Phil. Trans.']. 

 " On the Theory of Lubrication and its Application to 

 Mr. Beauchamp Tower's Experiments, including an Experimental 

 Determination of the Viscosity of Olive Oil " [originally published 

 in 1886, Phil. Trans.']; and "On the Dynamical Theory of 

 Incompressible Viscous Eluids and the Determination of the 

 Criterion " [originally published in Phil. Trans, for 1895]. Besides 

 these, there are several other papers of minor importance dealing 

 with the same subject. A very complete theory of the steam- 

 engine indicator and the various errors to which it is liable to give 

 rise, with an account of experimental investigations, is contained 

 in a joint paper by the author and Dr. Brightmore. Towards the 

 end of the volume, on pp. 631-733, we find a very full account of 



