576 



KNO\VL.E!3GE ♦ 



[Mav 



18«2. 



The forcgoin); facts I can personally testify to. 



Professor Ilu'ckcl classifies the true bony tishcs (Tehonlei) us 

 I'hyaostomi, or those in which the air-liladdor communicates 

 throughout life with the alimentary canal by an open duct ; and the 

 Phyuoclisti, in which the duct, though open in the young immature 

 fish, is closed in the adult. To the latter group (which is further 

 ehoracterised, according to Professor Iluxley, by the presence of a 

 rete mirabilo in the air-liladder) the cod belongs. 



To sum up the case, I coiilcnd: — 



1. That there is nir wilhiii the sound, which, unless produced by 

 yiosf mortem changes, would by all analogy certainly cause the 

 death of an animal if in its aorta. 



2. There is also within it a rete mirabile which miijht be mis- 

 taken for a blood clot, but 1 have never found any blood. 



3. There are, between the sound and the backbone, the kidneys, 

 which, in Mr. Williams' sludent-days, uiaij have been regarded by 

 anatomists as mere clots of blood, and it is obviously to them that 

 he refers as the " great dorsal blood clots," agreeing as they do 

 exactly in distribution with the said "clots." It is quite contrary 

 to my experience to find blood forming clots in arterica, though 

 they are almost invariably found in the veins of dead animals, and 

 it is more than doubtful if such definitely distributed ones could 

 form in a large sac like the cod-sound. 



4. The head kidney lies in front of, and therefore must be outside, 

 the sound. 



5. There is no communication between the circulatory system 

 and the sound, as is proven by injection. 



6. The sound has walls made up entirely of fibrous tissue, 

 and therefore is not comparable to Imman arteries, which have 

 mtiscnlar walls, as have those of all other animals. It could not 

 supply any force for the propulsion of the blood, being merely 

 elastic, and not possessing contractilitii. 



7. There being no systemic heai-t in these bony fishes, the dorsal 

 aorta cannot proceed from the fcitibtts arteriosuSj as suggested by 

 Mr. Williams. 



8. The " sound " of the cod originates as an " off-shoot from the 

 upper part of the digestive canal," jnst as the air-bladders of 

 other fishes do, and therefore is the precise homologue of those 

 structures ; and, whatever its true function may be, it certainly 

 plays no part in the circulation of the blood. Its strength is no 

 obstacle in the way of comparison with undoubted air-bladders, as 

 the carp (a much smaller fish) has an air-bladder almost as thick, 

 with an open duct ; and in the extinct genus, Ccelacanthiis (a 

 Ganoid), we actually find a bony air-bladder. Old Fo.ssil. 



BREAK FOE TWO-WHEELED VEHICLE. 



[393] — I have a small pony, about 9 hands high, that runs in a 

 small two-wheel ladies' basket carriage. He is a very useful and 

 sagacious pony, but vei-y frightened of going down hill, for fear he 

 should fall with the vehicle on him. I am advised by our country 

 cousins about here to whip him, and make him run down-hill. I 

 think this advice both cruel and unwise. I think my pony knows 

 as well as I do that he might fall. In order to mend matters, can 

 any of yotir numerous correspondents say if they have had any 

 experience with a break applied to a two-wheeled vehicle ? and 

 should be obliged by a description. 



I am quite aware that breaks to four-wheeled can'iages are 

 common, but with two wheels the ditficulty is, that wherever the 

 break is placed on the periphery of the wheel, the effect is to press 

 down the shafts on the pony's back. By applying the break to the 

 nave of the wheel, some objection to this is removed, but I am told 

 that it strains the wheels. And, also, should the break be on both 

 wheels— that is double? W. H. C. 



A PASSAGE IN "IN MEMORIAM." 



[39-i] — I consider it to be utterly impossible for the allusion to 

 be to Longfellow. Goethe is no doubt the poet referred to. Long- 

 fellow does not sing " in divers tones," whereas Goethe does. It 

 appears to me that what was in Tennyson's mind at the time of 

 writing was the manner in which Faust, in the second part of the 

 <lrama, finally works out his own salvation. The allusion is pro- 

 bably one in spirit, rather than in letter, though it is possible that 

 in the "conversations with Eckermann " some passages may be 

 found to throw light upon it. Tennyson himself has, I believe, 

 stated that the reference is to Goethe. 



Next as to dates of publication. " In Memoriam " appeared in 

 May, 1850 (though written years before), and the introduction is 

 dated 1840. Longfellow's poem is avowedly based upon a passage 

 in St. Augustine's " De Ascensioue" (De viliis nostris scalam nobis 

 Jncimus, si vilia ipsa calcamus), shows here and there slight and 

 unnsnal traces of Teunysoniau mannerisms, and forms part of the 

 First Flight of " Birds of Passage." So far as I can remember, 



this serien was published about 1858, probably as an appendix to 

 the ■' Miles Stundish " volume. This much may bo gleaned from 

 internal evidence. The poems appear to be chronologically arranged. 

 Those on the death of the Duke of Wellington and on Florence 

 Nightingale, for obvious reasons, could not have been written earlier 

 than 1H.52 and 18.^5 re8))ectively. I cannot give the date of "The 

 Two Angels," but it may easily be fixed by the event it refers to^ 

 the birth of one of Longfellow's children and the death of Mn. 

 Lowell on the same day. " Victor Galbraitli " may have been 

 written as early as 18W, and "The Jewish Cemetery" probably 

 sprang from the poet's visit to England. I think that " Daybreak" 

 appeared about 185tj (or somewhat earlier) in one of the magazines 

 edited by Charles Dickens, but I have no present means of ascer- 

 taining. The series clo.=es with "The Fiftieth Birthday of Agassiz," 

 which is dated May 20, 1857. just seven years after the ]iublication 

 of " In Memoriam." I believe, therefore, that the resemblance 

 between the passages in question is purely accidental, but that if it 

 be otherwise, Longfellow, not Tennyson, must be liold to bo the 

 copyist. I may add that the so-called parallel passages from 

 Petrarch and Milton need hardly be t.ikcu into consideration. 



George E. Dabtnell. 



ansftuerg to Corrcsfpontirnts. 



tmmum cations for the Editor requiring early attention nhnuld reach tks 

 before the Saturday prfeeding the current ianue of Knowlbdob, tiu 



irculation of which compel* iw to go to prenf early in the week. 

 Hints to Coerbspondbxts. — 1. A'o qnextiona aaking for Kcienttfic iiiforwuUum 

 can be answered through the post. 2. Lettert gent to the Editor for correspondetUa 

 cannot be forwarded ; nor can the namee or addret*e' of corretpondenta be given •■ 

 answer to private inquiries, 3. CorrespfrndenUt nhould vrite on one »ide onlg of 

 the paper, and put drawings on a separate leaf. 4. Each Utter thould have a title, 

 and in replying to a letter, r^erence thould be made U> its numbeTf the page <ra 

 which it appeartf and ita title, 



R. OusELEY. If your communication were not quite so long ! It 

 is so difficult to abridge satisfactorily. No; the gentleman to 

 whom yon refer is not my son, nor have I a son old enouffh for the 

 rank of colonel, unless thirteen years be considered a suitable age 

 in India. — C. J. Browx. The answers to correspondents will not 

 be abolished, but reduced in quantity. I ^ " "-'^fi to think that 

 some, at any rate, among readers have not misunderstood what was 

 meant — in aluiost every case — for good humour. Several have 

 taken for downright severity what 1 have meant for good-natured 

 fun. I do so thoroughly enjoy banter (I mean when I am bantered 

 myself), that I cannot qtiite understand how others can be hurt by 

 it. To give an instance, — one con'espondent, who really has some 

 very wild ideas about stone implements — which he regards as 

 natural formations — describes my jocular objections to hia 

 views as " worthy only of a palaeolithic savage." You are 

 right in thinking K. A. Proctor and the Editor of Know- 

 ledge one and the same indi\'idual. I never supposed it 

 would be thought otherwise, when I mentioned that the Editor (^ 

 KNOWLEDGE (R.A. p.) wished R. A. P., student of science, to go to 

 Egypt to observe the eclipse— which task, by the way, the latter 

 has been obliged, greatly to his regret, to decline. — Cl'RIOSITT. 

 Since noticed. Letters had been too multitudinous to be got 

 through. — G. H. P. Egyptian centres, area, period, and duration 

 of totality given this week. — J. S. Thanks for pointing out that 

 the doggrel rhymes about the borrowing days do not occur in the 

 " Complaint of Scotland," a prose work. Does it not seem as 

 though the observed coldness of those three days, which in the six- 

 teenth and seventeenth centuries were the first three days of April, 

 affords a sufficient reason for the conceit that March had borrowed 

 these days from April? in other words, that though April days in 

 name they are JIarch days in quality. — Decimal. The rule for 

 placing the decimal point in division of decimals, simple and recur- 

 ring, is given, I think, in most books on arithmetic. It is not veiy 

 concise, but is simple enough. I have forgotten it. But in practice 

 one does not need any rule of the kind. I timply set off the decimal 

 point of division as many digits to right or left as may suffice to 

 leave only one digit on the left of it ; and then set the decimal 

 point of dividend as many digits in the same direction, putting in 

 zeros if any are wanted. It then becomes obvious where the decimal 

 point of quotient must fall. Thus consider the following cases : — 



First. 127412)15 315( ; I write this, or conceive it written, thus, 

 l'27ll2)'15315(. Here manifestlv the quotient will begin 'l. 



Secondly, ]67-531)15'315( ; I write this 1-67531)153I5(, and 

 manifestly the quotient here will begin "09. 



Thirdly. 167-531)015315( ; I write' this 1-67531) •00015315(, and 

 manifestlv the quotient will begin '00009. 



Fourthly, 127-412)1531-5( ; " I write this 1-27412)153150(, and 

 manifestly the quotient mil begin 1, followed by five digits before 

 the decimal point. 



