Vlll CONTENTS OF VOL. XLV. — FOURTH SERIES. 



Page 



Notices respecting !New Books : — 



Dr. J. Anderson's The Strength of Materials and Struc- 

 tures 457 



Mr. GL J. Symons's British Bainfall, 1872 459 



"Weekly Weather Reports issued by the Meteorological 



Office 460 



Proceedings of the Greological Society : — 



Mr. H. Hicks on the Treinadoc Bocks in the neighbour- 

 hood of St. David's, South Wales 460 



The Bev. 0. Fisher on the Phosphatic Nodules of the Cre- 

 taceous Bock of Cambridgeshire 461 



Mr. "W. J. Sollas on the Ventriculitidse of the Cambridge 



Upper G-reensand 461 



American Astronomy 462 



On the sudden Cooling of Melted Griass, and particularly on 



" Bupert's Drops," by V. de Luynes 464 



On a Method of measuring Induced Currents, by P. H. Bigelow. 467 



Index . 469 



PLATES. 

 I. II. Illustrative of Dr. R. K6nig"s Paper on Manornetric Flames. 



III. Illustrative of Dr. A. M. Mayer's Paper on an Acoustic Pyrometer, 

 and Dr. A. Stoletow's on the Magnetizing-function of Soft Iron. 



IV. V. Illustrative of Dr. W. M. Watts's Paper on the Spectrum of the 

 Bessemer-flame. 



VI. Illustrative of Captain Noble's Paper on the Pressure required to 

 give Rotation to Rifled Projectiles. 



VII. Illustrative of Mr. O. Heaviside's Paper on Duplex Telegraphy. 



VIII. Illustrative of Mr. H. Wilde's Paper on some Improvements in 

 Electromagnetic Induction Machines. 



ERRATA. 



Vol. 44, page 522, line 5 from bottom, for therefore read therefor. 



Vol. 45 ; page 160, for paragraph 3 of Mr. Hudson's paper (commencing 

 "This point" &c.) substitute-. — 



This point can be easily tested experimentally as regards sound. Thus 

 a tense string with amplitude of vibration =2 ought to become inaudible at 

 twice the distance at which it ceases to be heard with amplitude =1, if the 

 square of the amplitude be the correct assumption. The relative distances 

 at which the sounds should be inaudible ought to be as 1 to 070715, if the 

 simple amplitude (not its square) be correct. 



