17Jr Scientific Intelligence. 



(3) What pressure is it best to select ? 



(4) What electromotive force at the contact should one em- 

 ploy ? 



The authors did not succeed in supplanting the galvanometer 

 by a microphonic contact for the detection of very feeble cur- 

 rents. — Ann. der Physik, No. 14, 1905, pp. 695-724. j. t. 



11. Mathematical and Physical Papers; by Sir George 

 Gabriel Stokes, Bart. Vol. V, pp. xxv + 370 (Cambridge 

 University Press). — This is the final volume of the collection and 

 covers the period from 1876 to 1903. It is well known that, dur- 

 ing these years and, in fact, for some time prior to 1876, Stokes 

 spent much labor upon his duties as secretary of the Royal 

 Society and as a member of its publication committee. These 

 duties were so conscientiously performed that (in the opinion of 

 those who knew him) they interfered greatly with his own work. 

 But the service to science which he thus indirectly rendered by 

 aiding, criticizing, and suggesting extensions of the work of 

 others, must have been very great. Some idea of this service 

 may be obtained from the present volume, which is largely made 

 up of notes and explanations appended to papers by other 

 authors in the publications of the Royal Society. One hitherto 

 unpublished paper upon Water Waves (written in ] 880) is 

 included, as is also the Wilde Lecture on the nature of Rontgen 

 rays, in which the accepted theory of these rays was first pro- 

 posed. A very interesting feature of the volume is the series of 

 examination papers which Stokes prepared, from time to time, 

 for the Mathematical Tripos and for the Smith's Prize Examina- 

 tion at Cambridge. 



In the preface, Prof. Larmor promises a further volume " of 

 biographical character, to be occupied iu part by a selection from 

 Sir George Stokes' voluminous scientific correspondence, includ- 

 ing some unpublished manuscript material" ; this will be looked 

 for with much interest and it is to be hoped that nothing will 

 interfere with its early publication. h. a. b. 



12. Lehrbuch der Physik ; von O. D. Chwolson. Band III. 

 Deutsch von E. Berg. Pp. xi-f 988. Braunschweig (F. Vieweg 

 und Sohn). — The first two volumes of this German translation of 

 the Russian text-book of Prof. Chwolson have been noticed in 

 previous numbers of this Journal. The present volume deals 

 with the theory of heat and has the same admirable qualities of 

 clearness, completeness and perspective which are so noticeable 

 in the earlier volumes. h. a. b. 



13. The Polariscope in the Chemiccd Laboratory. An Intro- 

 duction to Polarimetry and Related Methods / by Geo. Wm. 

 Rolfe, A.M., Instructor in Sugar Analysis in the Mass. Insti- 

 tute of Technology, pp. 320, 8vo. New York, 1905. (Macmillan 

 Co.) — It has happened, not infrequently in the past that Ameri- 

 can men of science, when impelled by one or another motive to 

 prepare elementary text-books, have produced works decidedly 

 superior to any analogous publications that had appeared previ- 



