May, 1901.] 



KNOWLEDGE. 



97 



Founded by RICHARD A. PROCTOR. 



VoL.ssn-.] LONDON: MAY, 1901. 



[No. 187. 



CONTENTS. 



■ PAOK 



The Size of Ocean Waves. — 111. By Vaughan CoBNisn, 



M.sc.(vicT.), r.c.s., F.B.G.s. {Illuxtra/ed) . 97 



Giant Ostracoda: Old and New. B_v the Eev. Thomas 



R. K. StKBBISG, M.A., F.K.S.. F.t.S., F.Z.S. .. ... . WO 



The Stronghold of the Nuthatch. A Story of Siege 



and Defence. By A. H. Macukll Cox. m.a 101 



Standard Silver: Its History. Properties and Uses. — I. 



By Krnest A. Smith. a?sipc.ii.s.:\i.. K.o.s. .. ... ... Iu2 



The Types of Sun-Spot Disturbances. By tlip Rev. 



.\. L. I'OIiTIE. S..I.. F.K.A.S. {J'lalf) ... 104 



Life-History of a Sun-Spot Group. (Plate.) 



Constellation Studies. — V. The Scorpion and the 

 Serpent- Holder. By E. Walteh Maunder, f.r.a.s. 



(IlluflratedJ ... " lOu 



The New Star in Perseus ... .. 107 



Letters : 



SrxspoTS AND Teheestriai Temperatttbe. By Percy 



QcENSEL. T.F.E. >'oto by E. Walter Maindeb . lOS 

 TaE Nedflae Hvpothesis. By Geo. McKenzie Knight lO'.i 

 The Xebclae Hypothesis. By William Xoble. Note 



by Eds " 109 



Constellation Studies. By Eenest L. Beilby. Xote 



by Eds ... . lo9 



Notices of Books . 110 



Books Keceiyed 112 



Notes ... 112 



The Insects of the Sea.— 111. Beetles. By Geo. II. 



Carpenter. b.bc.(lond.) (Illustrated) ... ... ... Ill 



British Ornithological Notes. Conducted by IIabkt F. 



WiTHEP.BY, F.Z S.. M.B.O.U. ... ... ... ... ... 116 



Microscopy. Conducted by M. I. Cross. 117 



Notes on Comets and Meteors. By W. F. Denning, 



F.R.A.S. . ... ' ... lis 



The Face of the Sky for May. By A. Fowler, f.e.a.s. ... 119 

 Chess Column. By C. D. Lococe, b.a 119 



THE SIZE OF OCEAN WAVES.-III. 



By Vaughan Coenish, ji.sc.(vict.), f.c.s., f.r.g.s., 

 Associale of the, Owens College. 



Ix a previous article I gave the results of Admiral 

 Cpupvent des Bois' attempt to connect the average 

 height of the waves with the strength of the wind. 

 The Table VI. embodying this result was the outcome 

 of about 7000 observations made on board the 

 Astrolabe. More recently Captain D. Wilson-Barker, 

 H.M.S. Worcester, has published* a table showing the 

 connection between wind and wave according to his 

 own experience. This extends over many years at sea, 



during wliicli he was nine times round tlio world in 

 sailing ships in liigh southeni latitudes, and made 

 many measurements of waves combined with simul- 

 tc-ineous observations on the strcoigth of the wind. 



TAin,K VII. 



Wind velocitv and corresponding soa disturbancp 

 (!). Wilson-Biirkrr). 



The tables of Paris, Coupvciit des Bois, and Wilson- 

 Barker ai'e not perfectly comparable throughout, but I 

 think we may venture to arrange in parallel columns 

 the four greatest values for average height of waves, 

 and to assume provisionally that they represent three 

 independent sets of obsci-vations of average height of 

 waves in deep water and open sea, during strong 

 breeze, gale, strong gale, and a gale of hurricane force. 



Table VIII. 



HoiLi'lit (if Wuves in feet. 



C. lies Bois. 



Pnris. 



Wilsoii-Hnrk(;r, 



Hurricane 

 Strong gale 

 Gule ... 

 Strong bi'eeze 



28-54 

 20-67 

 15-42 



Io-k:! 



25-43 



16-.'J7 



28 

 •J3 



14 



• Quarterly Jcmrnal of fheSoyal Meteorological Socieit/, V0I.XX.Y., 

 Xo. 109, .Tanuary, 1890, p. 15. 



With regard to the lengtli of waves, I think most 

 observers will agree that the greatest average length 

 of wave is not observed where the wind is blowing 

 strongly' but where the sea is heaving with a steady 

 swell in a comparatively calm atmosphere. Thus in 

 Lieut. Paris' record the maximum average wave length 

 for a single day (771 feet) occurs when the state of the 

 sea is described as (/ro-txe houle. a heavy swell, whereas 

 the greatest average length ,for a day of storm (trea- 

 grosse mer) was 590i feet. As the average force of 

 the wind for " trcs-grosse mer " was indicated by the 

 number 9, and that for " grosse houle " by the number 5 

 (on a scale of 0-11), the above appears to be the neces- 

 sary interpretation of Paris' figures. In this matter, 

 however, we are fortunately able to adduce other 

 evidence besides the observations made from ships at 

 sea. Observations of the intervals of time between the 

 breaking of the waves on shore are easily made, the 

 intervals of time are greater for the larger waves, and 

 the longer intervals are those recorded during " ground- 

 swells " in calm or comparatively calm weather. Thus 

 on December 29th, 1898, in the fine weather with north- 

 westerly breeze following a great storm accompanying 

 an atmospheric depression which had travelled quite 

 across the Atlantic, I obsei-ved at Branksome Chine 

 near Bournemouth, an uninterrupted scries of 139 



