5o6 



NATURE 



\April 2(), 1875 



rnrefiil anil experienced investigators as the Drapers, Von Monk- 

 Iioven, Spiller, Carey Lea, and others wlio have repeated Prof. 

 Vogel's experiments, should utterly fail to obtain any confirma- 

 tion of his hypotheses ; and there is no solution in accordance 

 with known facts and analogies of actinic action except to con- 

 clude with Dr. Draper that Trof. Vogel has made a mistake— he 

 lias attributed to one of two coincident qualities of certain sub- 

 stances effects which are due to the other. 



Dr. Draper records experiments in which he secured a photo- 

 graph of the entire spectrum on a daguerreotype plate, by avail- 

 ing himself of the singular reversing action of light on the 

 impressed plate (pp. 2 and 3 o' memoir), and allowing a diffused 

 daylight to fall on the plate simultaneously with the spectrum 

 image. " If," he says, "a spectrum be received on iodide of 

 silver formed on the metallic tablet of the daguerreotype, and 

 carefally screened from all access of extraneou<i light, both before 

 and during the exposure, on developing with mercury vapour an 

 impression is evolved in all the more refrangible regions. 



"But if the metallic tablet during its exposure to the spectrum 

 be also receiving diffused light of little intensity, as the light of 

 day or ot a lamp, it will be found, ondevelopinj, that the impres- 

 sion differs strikingly from the preceding. Every ray that the 

 prism can transmit, from below the extreme red to beyond the 

 extreme \'iolet, has been active. The ultra-red heat lines a j3 7 

 are present." 



The whole of this memoir is of the greatest interest to the 

 spectroscopic photographer, not only as giving the result of all 

 previous experiment in this field, but in clearly marking out what 

 remains yet to do in it. The subsequent success of the younger 

 Draper in obtaining a negative of the spectrum complete by tlie 

 ordinary collodion process, through the aid of an analogous 

 system of protection by mechanical means for the lines most 

 readily impressed, proves that even vrith silver, and under any 

 condition of process, we have the power of recording any spec- 

 troscopic phenomenon ; but if experiment should prove that 

 substances in themstlves liable to decomposition by rays which 

 do not attack the salts of silver are capable of communicating an 

 impression by molecular contact to the silver, and inducing 

 decomposition in it, it is evident that a complete combination 

 may be arrived at which, without mechanic il contrivances, will 

 give us printing negatives of the spectrum throughout. 



W. J. STILLUiK 



Dr. A. B. Meyer and his Critics 

 Not until now have I found leisure to look through the pages 

 of Nature for the years 1873 and 1S74, and therefore it was not 

 till now that I became aware of two letters in your correspon- 

 dence (December 11, 1873, p. 102, vol. ix., and April 23, 1874, 

 p. 482, vol. ix.), which concern me, and in answer to which I 

 htg leave to say a few words. 



The first is written by Mr. Wallace, and is about a wrong 

 opinion which I had formed on this au'hor's notion as I0 

 the relation of the inhabitants of the Arfak Mountains on New 

 Guinea to the inhabitants of the coast. I am glad to see that 

 Mr. Wallace and I agree in the conviction of the identity of 

 those two groups of Papooas ; but nevertheless I am anxious to 

 jhow that my misunderslanding of Mr. Wallace's opinion was 

 based upon an apparently clear expression in his valuable work 

 on the " Malay Archipelago," which I took, as I believe, not in 

 the restricted sense in which the author perhaps wished it to be 

 understood. Mr. Wallace did not succeed in finding the passage 

 in his work on which I had based my idea ; but he just breaks 

 (iff his quotation where the words begin to which I referred : 

 " Their hair, though always more or less frizzly, was sometimes 

 short and matted," &c. ; so far Mr. Wallace cites his own 

 words, but the sentence (page 310, 1st ed.) goes on, "instead 

 of being long, loose, and woolly ; and this seemed to be acLtiistitu- 

 lional differetice, not the effect oj care and cultivation." These 

 last words then led me to the opinion in question. In a paper 

 m the Mittheilunoen der Ant/no/^ologischen GeseUschafl s« ]\'ien 

 ( " Anthropologische Mittheilungen iilier die Papuas von Neu 

 tluinea; I. Ausserer physischer Habitus"), 1874, page 92, I 

 i|Uoted myself the jp/zo/f passage, and dealt with the object more 

 in particular. That It is still the general opinion that a difl'er- 

 ( nee exists between the Arfakis and the Papooas of the coast is 

 proved, e.g., by a notice of that paper in M. Broca's "Revue 

 d'Anthropiilogic," vol. iii., 1874, page 729 : "Notre voyageur 

 n'admet pas non plus qu'il y ait entre les tnbus du boid de la 

 mer et celles des montagnes — les Arfakis — les differences consti- 

 tutionelles obsenh cependantpar la flupart des voyageiirs," Sec. 



The other letter contains a protest of Signor D'Albertis 

 against my having " led the public to believe that he had claimed 

 for himself the honour of crossing New Guinea from one coast 

 to the other." Signor D'Albertis cites my paper in Nati;re, 

 vol. ix. p. 77, where he states he has read an assertion of mine 

 concerning this point. But I look in vain through my whole 

 article to find one single word to the purpose, and therefore I 

 do not understand what induced that intrepid co-operator to 

 publish his protest. I only mentioned (page 79) : " I need not 

 say that this journey from one side of New Guinea to the other 

 has never been made before, and I should hardly myself attri- 

 bute any importance to the fact," &c. A. B. MeyER 



The Chesil Bank 



The letter of your correspondent. Col. Greenwood (vol. xi. 

 p. 386), has only now been brought under my notice. 



There is one fallacy contained in it which no one would detect 

 more easily than Col. Greenwood, if he were but to visit the 

 Portland end of the Chesil Bank. He would then see for him- 

 self that Portland Island does not act as a groin in accumulating 

 the pebbles that form the beach. 



The Chedl Bank extends from Portland to Bridport Harbour, 

 where it is composed of small pebbles or gravel of the average 

 size of horse-beans. It is there a true beach of considerable 

 breadth and depth, and does not merge into sand until it arrives 

 .it a point beyond the mouth of the harbour. Following it 

 towards Portland, it runs along under the cliffs by Burton, Swyre, 

 &c., to Abbotsbury, where it assumes its distinguishing charac- 

 teristic of a pebble ridge, washed by the sea on one side and by 

 the waters of the Fleet estuary on the other. From thence it 

 proceeds to the Ferry bridge, where it meets the waters of Port- 

 land Roads (from which, however, it is separated by a stretch ot 

 sand of varying width), and from thence to Portland. 



Its direction after leaving Abbotsbury is W.N.W. and E.S E. 

 very nearly. On reaching Portland it takes a sharp curve to the 

 west and forms the little bight called Chesil Cove, and it is here 

 that the ridge begins to decline in height, and the pebbles, that up 

 to this point have been gradually increasing in size, commence to 

 diminish in bulk. A line stretched seawards from this point at 

 right angles with the shore would point W. S.W. 



The decline is rapid, so that in a distance of about 250 yards 

 the bank tails out to nothing at the point where it touches, and 

 does but just toucii, the Undercliff. 



There are probably several causes at work in bringing about 

 this abrupt termmation of the Chesil Bank. Among them I 

 should reckon as most effective the curvature of the bank at 

 Chesil Cove, whereby the beach is exposed at such an angle to 

 the waves caused by the prevailing S.W. wind that the progres- 

 sive action of the W. and W.N. W. winds is neutralised; secondly, 

 the peculiar set of the tides round the Bill at Portland ; and 

 thirdly, the progressive action of the W. and W.N.W. winds 

 being diminished or nullified by the curvature. 



There cannot be the slightest doubt that the march of the 

 pebbles is from Bridport to Portland, and that any movement in 

 the contrary direction is due to temporary causes only. 



That the larger pebbles travel over the heads of the smaller 

 when the waves strike the beach at an angle is not merely pro- 

 bable in theory, but a fact demonstrable by experiment, as was 

 announcef by Sir John Coode in his elaborate paper on "Sea- 

 Beaches " (I'hil. Trans. 1S34). 



As to the materials of the beach having been partly derived 

 from the destruction of the ancient raised beach, the remains of 

 which are to be seen at this day in Portland, I would remark 

 Iha', according to the account given by Leland inhis"Itinerar5'," 

 Portland at the time of his visit wis of ne rly the same dimensions 

 as now, though tradition reports that the site of the old church 

 was once the c-ntre of the island, the shifting bank of sand and 

 shells called the Shambles being is eastern boundary. Any 

 pebbles derived from the intervening raised beach have in all 

 probaliility been ground by thecoaiinual pounding of the Atlantic 

 billows into sand long before this — probably before the time of 

 Iceland. Vet he states, with reference to the Chesd Bank, 

 " that as often the wind blowith strene at soulh-est (? west) so 

 often the se betith it, and losith the bank, and breakith titroiigh 

 it ; " indicating that the bank was not so strong then as it is now : 

 for such a thing has not occurred within tlie memory of living 

 man, not even on the occasion of the " Outrage" in Nov. 1823, 

 when the crown of the bank was swept off by a tremendous gale, 

 and spread over the sands on the otiier side ol the ridge ; when 

 the fishermen's houses, that_for centuries probably had nestled 



