132 



NA TURE 



\_Dec. ii, 1884 



complete investigation of the stability of a ship at angles 

 considerably beyond those to which the metacentric height 

 is a fair measure of the stiffness." He also speaks of the 

 " stability of a ship up to 6o° of inclination." This is a 

 strange although common misuse of the term " stability." 

 Stability only exists at a position of stable equilibrium, 

 and what is really meant by the above-quoted sentence is 

 not stability at large angles of inclination, but righting 

 force. 



The other paper upon stability, which describes a 

 method of approximation to curves of stability from data 

 for known ships, is interesting in showing how some of 

 the elements of stability vary in a ship with the ratios of 

 draught of water to depth, and depth to breadth ; but we 

 cannot regard it as likely to be of much value in prac- 

 tice. The approximations obtained by applying the 

 method are only reliable when the form of the vessel for 

 which the curve of stability is required, and that of the 

 one which is being used for estimating it from, are so 

 related to each other that any section of the one may be 

 obtained by projection from the corresponding one of the 

 other. Differences in form are excessively numerous — 

 almost universal indeed — among ships ; and small discre- 

 pancies of such a kind often affect stability to an im- 

 portant degree. When vessels are found to belong to 

 what is defined in the paper as a " type-form," the method 

 is applicable, but where no true type-form can be dis- 

 covered for a particular ship — and this is what usually 

 happens in practice — the only reliable and also the readiest 

 mode of approximation to a curve of stability is to 

 compute by means of Amsler's integrator the true length 

 of a small number of ordinates of the curve. 



There are other papers of interest in this volume which 

 are amply deserving of perusal, though we have not space 

 for referring in detail to them. We may note, however, as 

 an indication of the active and enlightened interest taken 

 by Scotch engineers in scientific teaching, that the Pre- 

 sident of the Institution of Engineers and Shipbuilders in 

 Scotland — in referring at one of the meetings to the 

 endowment of the John Elder Chair of Naval Archi- 

 tecture in Glasgow University, which is filled by Prof. 

 F. Elgar — said that " the Council had agreed, and 

 were morally bound, to support the institution of a lecture- 

 ship in anticipation of a Chair of Naval Architecture in 

 the University." Mr. Reid further stated that " the Council 

 had agreed to continue the lectureship in connection with 

 the Chair," and he wished it to be known that the original 

 intention was still to be carried out. This is a strong 

 practical proof of the earnestness and wise liberality of 

 Scottish engineers in the matter of scientific and tech- 

 nical education, and it is a policy which cannot fail to 

 largely benefit the district in time to come. It is also one 

 indication, out of many, of the advantages which may 

 confidently be looked for by engineers and scientific men 

 as the natural outcome of such institutions as those we 

 have referred to. 



THE EGGS OF MONOTREMES 



SPEAKING at the anniversary meeting of the Royal 

 Society in November 1883, Prof. Huxley said : — 

 " It certainly was high time that British science should 

 deal with a problem of the profoundest zoological in- 

 terest, the materials for the solution of which abound 

 in, and are at the same time confined to, those territories 

 of the Greater Britain which lie on the other side of the 

 globe." These words had reference to the series of in- 

 vestigations which Mr. Caldwell— the first Balfour Student 

 — had then gone to Australia to prosecute with regard to 

 the embryology of the lowest Mammalian forms, the 

 Monotremes and Marsupials. 



Somewhat less than a year later, and whilst the British 

 Association was holding its meetings in Montreal, Prof. 

 Moseley, the President of the Biological Section, was 



enabled to communicate the following brief but suggestive 

 message telegraphed from Australia : — " Caldwell finds 

 Monotremes oviparous ; ovum meroblastic." Brief as 

 was the message, it yet, as Prof. Moseley said, con- 

 tained the most important scientific news which had been 

 communicated to the Association in Canada. 



Zoologists will now look forward with deep interest to 

 the publication of Mr. Caldwell's more detailed account 

 of his recent investigations, which have apparently 

 enabled him to confirm so fully what has before been 

 suspected, but never actually proved to be the case. 



That Monotremes are oviparous has been maintained 

 by various naturalists for now some sixty years : but up 

 till the present time no sufficient evidence has been 

 brought forward to place the matter beyond dispute, the 

 chief difficulty in elucidating the problem lying in the 

 fact that the two curious groups of animals which alone 

 are placed in the Monotremata inhabit exclusively the 

 Australian region, and hence have been but little studied 

 in their natural habitat. 



Though they are closely allied, yet the Ornithorhynchus 

 and Echidna differ markedly from each other in external 

 appearance — the one being adapted to the water, having 

 its feet webbed, and its muzzle of that peculiar shape 

 which has earned for it the name of Duck-billed Platypus, 

 whilst the other is essentially a iand animal, feeding on 

 ants which it licks up by means of a long flexible tongue, 

 and having its body covered with sharp spines, much as 

 a hedgehog. 



The question of how these animals reared their young, 

 and in what condition the latter were born, has long been 

 a matter of much dispute, and for information we are 

 principally indebted to the memoirs of Home, Meckel, 

 Geofffoy St. Hilaire, and perhaps most of all to Owen : 

 whilst from time to time short notices are to be found in 

 the Proceedings of the Zoological Society and the Journal 

 of the Linnean Society. 



In 1829 Geoffroy St. Hilaire laid a communication 

 before the Royal Academy of Sciences in Paris, entitled 

 "Considerations sur les ceufs d'Ornithorinque formant 

 de nouveaux documens pour la question de la classifica- 

 tion des Monotremes." ' Herein he stated his opinion 

 that the Monotremes could no longer be admitted amongst 

 the mammals, nor could they be classified with either 

 birds, or reptiles, or fishes, but they must, though includ- 

 ing only two groups of animals, be formed into a distinct 

 fifth class among the Yertebrata, which would hence be 

 divided, according to him, into Mammals, Monotremes, 

 Birds, Reptiles, and Fishes. 2 The most interesting part of 

 his paper, from our present point of view, however, consists 

 of a letter which he quotes in full from Prof. Robert E. Grant 

 of London, who describes in some detail the finding by 

 a certain Air. Holmes, whilst shooting on the banks of 

 the River Hawksburgh in Australia, of a nest of eggs 

 laid by an Ornithorhynchus ; the animal was seen to 

 hasten away from a sandy bank and plunge into the 

 water. Examination of the bank led to the discovery of 

 a small burrow, in which, on a rude nest made of twigs, 

 were deposited nine eggs of a peculiar shape and size, 

 which rendered them clearly distinguishable from those 

 of any bird. The eggs, he says, are remarkable " par 

 tine forme reguliere spheroi'dale oblongue, par une 

 egale largeur a chaque bout ; ils ont (mesure anglaise),en 

 longeur de pouce, 1$, et en largeur of ; la coquille est 

 mince, fragile, legerement transparente, et d'une couleur 

 uniforme d'un blanc mat ; sa surface exterieure, vue a la 

 loupe, prdsente une texture d'un reseau admirablement 

 re'ticuld ; la matiere calcaire a produit les parois blanches 

 de ses innombrable et tres-petites cellules, ce qui n'em- 

 peche pas que la surface n'en demeure a peu pres polie. 



■ A/males des Sciences Katurclles, t. xviii. p. 162 ; also Bulletin dc la 

 SocitU Philomathique, t. viii. p. 95. 



- The same idea is to be found also in Lamarck, Philosophic Zoologique, 

 t. i. p. 145. Lamarck adds, further, " Ce ne sont point des 

 car ils sont sans mamelles, et tres-vraisemblablement ovipares." 



