Miscellaneous Intelligence. 403 



nent, is also clearly marked, the maximum occurring as a rule 

 between 9 a. m. and noon and between 9 p. m. and midnight. 

 Other minor harmonic components are also occasionally important, 

 the first maximum of the eight-hour component probably occur- 

 ring about 6.30 a. m., and that of the six-hour component about 

 3 or 4 a. m. ; but for these two epochs the results are not always 

 concordant. 



(3) Though the materials are insufficient for any general con- 

 clusion, the weaker shocks seem to be subject to a more marked 

 diurnal periodicity. 



(4) In the case of after-shocks of great earthquakes, the diurnal 

 periodicity is as a rule strongly pronounced. The maximum of 

 the diurnal period, occurs within a few hours after midnight, but 

 the epochs of the other components are subject to wide variation, 

 possibly on account of the short intervals over which the records 

 extend. A special feature of after-shocks is the prominence of 

 the eight-hour and four-hour components. 



The epochs of the first four components representing the diurnal 

 variation of seismic frequency are compared in several cases with 

 those for barometric pressure and wiud velocity. While the 

 variation of the former cannot be attributed exclusively to either 

 of the latter phenomena, it seems not improbable that the diurnal 

 periodicity of ordinary earthquakes may be due chiefly to that of 

 wind velocity, and the diurnal periodicity of after-shocks chiefly 

 to that of barometric pressure. — JProc. Roy. Soc, London, vol. lx. 



2. Transactions of the American Microscopical Society ; 

 edited by the Secretary. Eighteenth Annual Meeting held at 

 Cornell University, Ithaca, N. Y., August 21, 22, and^23, 1895. 

 Volume xvii, 376 pp., Buffalo, 1S96 (The Wenborne-Sumner Co.). 

 — This volume gives a iull accouut of the Eighteenth Annual 

 Meeting of the American Microscopical Society with the papers 

 then read. Among these may be noted the following, all of 

 which are illustrated by plates : Some modifications of stems and 

 roots for purposes of respiration, by H. Schrenk; The lateral 

 line system of sense organs in some American Amphibia and 

 comparison with Dipnoans, and On the Spermatheca and methods 

 of fertilization in some American newts and salamanders, by Dr. 

 B. F. Kingsbury ; Comparative Morphology of the brain of the 

 soft-shelled Turtle and the English Sparrow, by Susanna P. Gage. 

 The next meeting of the Society will be held at Pittsburg, Pa., 

 August 18 and 20, 1896. 



3. Handbook of Arctic Discoveries, by A. W. Greely, 257 

 pp., 12mo. Boston, 1895 (Roberts Brothers, Columbian Knowl- 

 edge Series, No. 3). — The interest and value of this little vol- 

 ume are quite out of proportion to its size. It deals with a 

 subject which has not only the highest interest from the scientific 

 side, but which perhaps more than any other tends to excite the 

 imagination of the general public. Notwithstanding its brevity 

 it gives a well-digested and very readable account of Arctic ex- 

 plorations from the earliest times. Its interest is increased in no 



