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NA TURE 



[March 22, 1900 



LETTERS TO THE EDITOR. 



[ The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, refected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.'\ 



The Rostrum of •' Mesoplodon." 



In Mr. Beddard's recent and very interesting " Book of 

 Whales," I observe that on p. 214 he gives as a character 

 of Mesoplodon (one of the Ziphioid genera) "the thorough 

 ossification of the mesethmoid," and in describing Berardius he 

 states that " the mesethmoid plate is short, comparatively 

 speaking ; that is to say, compared with what we find in 

 Mesoplodon." Here Mr. Beddard undoubtedly compares, two 

 structures which are entirely different. As I have shown and 

 figured in the P.Z.S., February 1893, the " mesorostral bone" 

 is not the result of the ossification of the cartilaginous bar 

 occupying in early life the spout of the animal's vomer. I have 

 examined a number of these Cetaceans in the flesh, and have 

 made sections of the dried beaks (a series of which I deposited 

 in the British Museum) of individuals of ages from the quite 

 young calfs to that of the very adult male, and I have shown 

 in the paper referred to that the first appearance of the meso- 

 rostral bone is due to an increase in the walls of the premaxil- 

 laries by which the sides of the vomerine-spout are pressed 

 towards each other, and, proliferation being apparently induced, 

 both the vomer and the premaxillaries increase in size, and very 

 variously in form, according to pressure unequally acting on 

 them, till the cartilaginous bar is entirely absorbed or, at all 

 events, disappears. The increase — from some pathological 

 cause, probably — in the premaxillaries is apparently the main 

 cause of the solidification of the beak. 



Now what happens in Berardius is of an entirely different 

 character. In B. arnuxiia.n ossified bar lies, often to a length of 

 twelve inches, in the vomerine trough ; but this is unmistakably 

 an ossification of the anterior part of the mesethmoid cartilage. 

 It takes place in a very different way, also, from the ossification 

 in Mesoplodon. It is an ossification of the upper and outer 

 layers of the mesethmoid cartilage ; it is of an open and spongy 

 texture ; it never becomes ivory-fied, so that in the dried skull 

 it is a mere prolongation of the mesethmoid— hardly seen in 

 Mesoplodon — and merely covers in to some extent the gape of 

 the vomerine trough, which underneath is quite empty, with its 

 sides and bottom entirely unaffected. Indeed, the mesethmoid 

 plate, with its extension, is in Berardius much longer than in 

 Mesoplodon. What takes place in the former genus is precisely 

 what occurs so frequently in Clymeiiia. 



In a note on page 280, Mr. Beddard writes, " the Scottish 

 vernacular for this creature [Globiocephalus] ' Ca'aing Whale ' 

 means Driving Whale." The proper orthography of " ca'aing " 

 should be " ca' in" (two words), which being interpreted out 

 of, to the Southerner, its foreign tongue, means " the drive in- 

 or driven in-vvhale." Ca'a is entirely erroneous. Ca' (in 

 Orkney, Kaa), as it should be printed, stands for "call." In 

 the common order to the herd on a Scottish farm of " Ca' in 

 the Kye " (meaning " Drive in the Cows ") the expression arises, 

 doubtless, from the custom of the past— which is the custom 

 to-day, as I have seen in New Guinea in regard to their pigs, 

 and in Sokotra last year in regard to the flocks and herds— of 

 actually by voice ' ' calling in " the cattle. The phrase has now 

 become the common one to " drive in," by some one going for 

 them. The method of capturing the Globiocephalus in the north 

 of Scotland is for the fishers, when they see a school, to hurry 

 out in their boats, surround and drive on to the beach the Black- 

 fish, which is, therefore, always spoken of there as the "Ca' in 

 Whale," i.e. the whale they can driva in, in contradistinction 

 to a species which they have to harpoon or chase in the open. 



Henry O. Forbes. 



The Museums, Liverpool, March 2. 



Vector Diagrams. 

 In a paragraph on the last number of Terrestrial A.agnetism, 

 in Nature of March i, p. 421, I notice the following sentence ': 

 "Dr. Ludeling investigates graphically the phenomenon of the 

 diurnal variation of the earth's magnetism for eleven stations 

 with the aid of von Bezold's vector diagrams." These diagrams 

 are curves in which the radius vector represents in magnitude 

 NO. 1586. VOL. 61] 



and direction the resultant of the disturbing forces to which we 

 may attribute the diurnal variation of the horizontal component 

 of the earth's magnetic force at any particular station. 



So far as I know, the earliest use of these curves by von 

 Bezold was in a paper in the Berlin Sitzungsberichte of 1897. 

 This may have been their first appearance in Germany, and if 

 so, their association with the well-known name of von Bezold 

 in that country need hardly occasion surprise. In England, 

 however, their use dates from at least 1863, when Airy employed 

 them in discussing the diurnal variation at Greenwich in different 

 years and at different seasons of the year (see Phil. Trans, for 

 1863). Airy used them again in the Phil. Trans, for 1885, and 

 they also appear on p. 186 and on Plate iii. of Lloyd's " Treatise 

 on Magnetism, General and Terrestrial." More recently I em- 

 ployed them myself in discussing the diurnal variation of the 

 magnetic elements at Kew Observatory (5. A. Report for 1895, 

 pp. 209-227) 



The only apparent difference between Airy and von Bezold is, 

 that the former made use of the recorded variations of horizontal 

 force and declination, drawing his magnetic meridian towards 

 the top of the page, whereas the latter made use of the northerly 

 and easterly (or westerly) components of the force, and drew his 

 astronomical meridian towards the top of the page. The curves 

 given by Airy and by myself show the positions of both the 

 magnetic and astronomical meridians, and if it is preferred that 

 the astronomical meridian should point to the top of the page, 

 all that is necessary is a bodily rotation of the curves through 

 an angle equal to the declination. 



When comparing results at different stations, or at the same 

 station at different epochs, there may be an advantage — as, in 

 fact, I pointed out myself (/9. A. Report, loc. cit. pp. 218, 219) — 

 in taking the astronomical meridian as the line of departure ; but 

 as yet this is largely problematical. The interesting tables and 

 diagrams for polar stations given by Liideling— as Liideling. I 

 think, has himself noticed — seem to indicate, on the whole, 

 less symmetry about the astronomical than about the magnetic 

 meridian. If so, it is open to doubt whether Airy's original 

 practice might not, after all, have been the better fitted to bring 

 out points of resemblance. C. Chree. 



Richmond, March 8. 



Similar Geological Structures in South Tyrol and the 

 Isle of Man. 



It may be of interest to Alpine geologists to note that the 

 general results now obtained by Mr. Lamplugh in the Isle of 

 Man are, in respect of the origin of the "Crush-Conglomerates " 

 and the causes and effects of differential movements between 

 subjacent series of rock, practically the same as the results 

 previously obtained and described by me in maps and sections 

 of the Enneberg area in South Tyrol (Quart. Jouni. Geol. Soi., 

 cf. M. M. Ogilvie Gordon, 1899, and G. W. Lamplugh. 1900). 

 In both cases the geologist deals with resultant local effects 

 combining the pressure-components of at least two epochs of 

 disturbance. In both cases the geologist is presented with 

 strongly-marked lithological contrasts in the original succession, 

 and, as a consequence, with highly complex superinduced 

 structures due to differential movements between subjacent 

 beds. This remarkable parallelism between the essential 

 geological structures in two neighbourhoods so remote from one 

 another, and in belts of strata belonging to utterly distinct 

 geological epochs, is well worthy of comment and consideration 

 by our present school of geologists. 



Aberdeen, March 16. Maria M. Gordon. 



Tides along the Antarctic Continent. 



In Prof. Drygalski's statements (Nature, February i) of the 

 work mapped out for the proposed German Antarctic Expedi- 

 tion, no mention is made of obtaining tidal observations along 

 the Antarctic Continent. In ascertaining the verae causae of 

 tides which occur along many shores, even along the eastern 

 coast of the United States, I lielieve this region to be of great 

 importance. 



Hourly readings of the height of the surface of the sea above 

 an arbitrary datum for even so short a period as twenty- four 

 hours at each station occupied for the purpose, would be of value. 



It seems to me especially desirable to have the following 

 questions answered : — 



(i) Along the Antarctic lands from long. 20° W. to about 

 40° E., is the (Greenwich) co tidal hour vi. ? 



