XXXI. Reviews, and Notices respecting New Books.

A Practical Treatise on Locomotive Engines upon Railways; with Practical Tables, giving at once the Results of the Formula, founded upon a great many new experiments, &c. By the Chev. F. M. G. De Pambour.

IT

Tis only within the last few years that the attention of engineers has been particularly directed to the mechanical capabilities of locomotive engines; and their inquiries have, for the most part, been limited to the vague practical information that is commonly inferred from actual experiments. The vast and splendid projects that now occupy such an important position in the public mind, and that promise such extensive and permanent advantages to society, have created a stronger and more lively interest in the science of railways. An engineer is expected to be, at least, practically acquainted with the theory of locomotive engines; he is supposed to possess that intimacy with the laws of their physical and mechanical action, as to be prepared to estimate pretty nearly, on scientific principles, the speed with which any proposed engine will draw a given load. How far this has really been the case is a question on which it will not here be necessary to offer an opinion; but we may state, that in the first stages of this, as well as of almost every useful branch of science, the practitioner is obliged at first to glean his information from experience alone. The construction of each successive engine suggests new and valuable information as to defects that may in future be avoided and improvements that may be adopted. The working of each engine also furnishes the means of roughly estimating what may be done by any other of a similar construction. Afterwards, however, when the subject becomes to be scientifically discussed, methods are presented by which the capabilities of any intended engine may be previously submitted to an accurate calculation, whatever may be the plan of its construction. We do not think that this object has yet been fully accomplished. The author of the present work, however, treats the subject in a manner that shows him to be well acquainted with the mechanical theory. He first gives a very intelligible description of the locomotive engines employed on the Liverpool and Manchester railway, as well as an account of their dimensions and proportions. He founds the calculations throughout the volume, on a great number of experiments that he has made himself with these engines. In the second chapter he gives rather a tedious discussion relating to the calculations of the true pressure of the steam from the indications of the lever and valve of the boiler: this might be abridged with advantage. The fourth and fifth chapters, which treat on the resistance along the railway and the proportions and effects, form the principal feature of the volume, and they contain a remarkably clear and comprehensive discussion of these most important points. The author very properly considers the friction of the engine separately from that of the load, and shows that in consequence of the additional strain on the machinery, it in

creases as the load increases. He also shows, that the rate of travelling with a given load does not depend solely on the tractive power of the engine, but that another important element enters into the calculation, viz. the evaporating power of the boiler. An appendix contains a detailed account of expenses, profits, and other valuable particulars of a mercantile and speculative nature, drawn from the documents of the Liverpool and Darlington railways. Altogether, the work is written in a clear and unaffected style; the subjects throughout are treated very philosophically, and with great ability; the typographical execution is also exceedingly creditable, and, judging from the gratification we have experienced on its perusal,we can have no hesitation in pronouncing it an elegant and truly valuable publication, that should be possessed by all persons interested in such pursuits.

XXXII. Proceedings of Learned Societies.

Dec. 22, SPEC

ZOOLOGICAL SOCIETY.

PECIMENS were exhibited of numerous Shells of the 1836. genus Mitra, Lam., and of one species of Conœlix, Swains., forming part of the collection of Mr. Cuming; and an account of them by Mr. Broderip was read, commencing as follows: The species of the genus Mitra, Lam., which I am about to describe had been sent by Mr. Cuming, in whose cabinet they are, to Mr. Swainson, whose intimate acquaintance with this family renders him so particularly competent to the task of describing them. They were named by him, and he also made notes respecting them before returning them. In the following account of them I have retained Mr. Swainson's name in every instance but one: and whenever he has made any written observations I have quoted them.

Characters, habitats, &c. of the following species were then given, and are printed in the "Proceedings."

Genus MITRA (Lam. and Swains.). Mitra nebulosa (representing nubila, Type 5, 1, Sw.), Swainsonii (Type 1, 1.), Ancillides (5, (2?)), maura (representing Tiara foraminata, Type 1, 4.), fulvescens (5, 1.), testacea (5, 1. representing fulva), fulva var. (1, 2. representing Tiara), chrysostoma (5, 1. representing ferruginea), tristis (2, 4.), and effusa (1, 5.).

Genus TIARA, Swains. (MITRA, Lam.) Tiara foraminata (representing Mitra maura, Type 2, 4.), muricata, mucronata, catenata (1, 3.), multicostata, rosea (1, 2.), millecostata (the close-set longitudinal ribs and cancellated base give this shell, which may not have attained its full growth, the aspect of a Cancellaria), lineata (5, 1), nivea (5, 3.), aurantia, terebralis, crenata (5, 3. or 3, 3.), rubra (1, 2.), semiplicata, and attenuata (5, 1).

Mr. Swainson had written on the paper containing Tiara terebralis, "Type 4, 4. This is one of the most extraordinary shells in the collection, as it so closely resembles the Mitra Terebralis that,

but for its possessing the generic characters of Tiara, it might pass for the same species."

It is one of the most slender of its genus, and has very much of the general character and form of a Terebra; and its resemblance to Terebra is increased by the circumstance of its having one spiral groove, more deeply impressed than the others, placed at about one third of the length of each volution before the suture. The points of contact of the decussating with the longitudinal grooves are deeply impressed.

There is a fine specimen in Mr. Broderip's collection.

Mr. Sowerby has furnished me with the account of this species. Genus CONOELIX (Swains.). Conoelix Virgo (representing Conus Virgo).

The following observations by Mr. Swainson elucidate his notes in relation to the Mitres, appended to most of the characters of the shells above named :

"To render my explanation of the notes and references attached to the different species of the Mitrane more intelligible to conchologists, it will be necessary for me to state, in as few words as possible, the result of my investigation of this subfamily, and the principles which have regulated these numerical indications.

'I have already, in another work, characterized the family Volutida, which appears to be that primary division of the Carnivorous Gasteropoda (Zoophaga, Lam.), which represents the Rasorial type among Birds, the Ungulata among Quadrupeds, and the Thysanura among perfect Insects (Ptilota): these analogies being of course remote, although founded on the structure of the animal, no less than on its testaceous covering. It thus follows that the Lamarckian Mitra, instead of a genus, constitute a subfamily, which appears to be the subtypical group of the circle. The five genera composing this circle I have long ago characterized; and here, for some years, my analysis of the group terminated. The inspection, however, of the numerous species brought home by Mr. Cuming, and the gradually augmented number in my own cabinet, seemed to invite a still further and more minute investigation, for the purpose of ascertaining if any, and what, subgenera were contained in the more crowded groups of Mitra and Tiara. This investigation was carried on, at intervals, for nearly twelve months; and the result surpassed my most sanguine expectations. It has convinced me that not only does each of the genera of the Mitranæ represent analogically the corresponding groups of the Volutine, but that the same relations can be demonstrated between the minor divisions of the genera Tiara and those of Mitra: in other words, that these latter represent all the subfamilies and genera of the other Volutide, while they preserve their own peculiar or generic character. What I have just said on the parallel relations of analogy between the Mitrane and the Volutida, is strictly applicable, in fact, to the genera Mitra and Tiara, the primary divisions of each of which can thus be deemon strated subgenera. Nor is this all: the materials I have been for so many years collecting have enabled me to ascertain, in very many

instances, that the variation of the species, in each of these subgenera, is regulated on precisely the same principle. Hence it follows that the two circles of Mitra and Tiara, like the two divisions of Mr. MacLeay's Petalocera, contain species representing each other, so that if their generic character is not attended to, it is almost impossible to discriminate them even as species. Many instances of this extraordinary analogy might be mentioned, independent of that here alluded to, between Mitra Terebralis and Tiara Terebralis.

66

Selecting this shell to illustrate the numbers "Type 4, 4," I may observe, that Type 4' signifies that it belongs to the fourth subgenus of Tiara, in which group it is the fourth subtype, uniting to Mitra maura, which is the fourth subtype of the first or typical subgenus. Mitra maura, again, as representing this latter shell, consequently becomes the fourth subtype of the first or typical subgenus, and is therefore marked "Type 1, 4." The first figure always denotes the subgenus, and the last the station which the species appears to hold in its own subgenus.

I am unacquainted with any group in the animal kingdom which demonstrates more fully than this does the law of representation. It may be mentioned, also, that nearly all the divisions I had long ago characterized, from the formation of the shells alone, have more recently been confirmed by a knowledge of their respective animals: a knowledge for which we are entirely indebted to the able naturalists who accompanied the French expedition on board the Astrolabe."-W. S.

Specimens were exhibited of several hitherto undescribed Cowries, most of which have been brought to England within the last few years. They were accompanied by characters and descriptions by J. S. Gaskoin, Esq., which are given in the "Proceedings" under the following names, viz.

Cypræa formosa (Cape of Good Hope), rubinicolor, producta, candidula (Mexico, Cyp. approximans, Beck, Cyp. olorina Duclos, but first described by Mr. Gaskoin), acutidentata (Isle of Muerte, Bay of Guayaquil), Pediculus, var. labiosa, vesicularis (Cape of Good Hope), and Beckii.

There was read an "Extrait du Quatrième Rapport Annuel sur les Travaux de la Société d'Histoire Naturelle de l'Ile Maurice : par M. Julien Desjardins."

The communications relative to the Mammalia read before the Natural History Society of the Mauritius in the fourth year of its existence have comprised an account by the secretary, M. Julien Desjardins, of a Whale which he regards as the Physeter macrocephalus, Linn., that was cast ashore on an adjoining reef: and some observations by the same author on several of the Mammalia of the island, and particularly on the hybernation of the Tenrec, Centenes spinosus, Ill.; the lethargy of which animal takes place when the thermometer is not lower than 20° Cent., and even when it marks 26°.

In ornithology M. Desjardins has also been the only contributor. He has described, as new, two Birds belonging to the island, and has

proposed for them the names of Charadrius Nesogallicus and Scolopar elegans.

M. Liénard, the elder, has, in the course of the year, described many Fishes, including a new species of Plectropoma, allied to the Plectr. melanoleuca, Cuv. & Val., which is of a uniform brown colour, with all its fins of a still deeper brown, except the pectoral which are orange; on this latter character his specific name is founded: a Holacanthus, La Cép., from Batavia, remarkable on account of the numerous sinuous silvery lines which occupy principally the middle of the body; and having also on its face two yellow and two black bands, one of which is ocular: a Cheilinus, Cuv.: an Echeneis, Linn., furnished, on its suctorial disc, with twenty-five pairs of plates: and a Muræna, Thunb., the body of which is of an ebony black, and the dorsal fin yellow; the trivial name being indicative of the latter peculiarity. He has also given some account of a collection of Fishes obtained from the western coast of Madagascar, and comprising thirteen species, several of which he regards as new. M. Desjardins has described as the blue-faced Tetrodon, a species remarkable for two large blue spots on each side of its face, and having the fin-rays as follows; D. 15. A. 12. P. 14. C. 14.; it inhabits the seas adjacent to the Isle of France.

In entomology the only communication made to the Mauritius Society was by M. Goudot, and related to the Insect described by Mr. Bennett at the Meeting of the Zoological Society on January 22, 1833, (Proceedings, Part i., p. 12; Lond. and Edinb. Phil. Mag., vol. ii. p. 478,) under the name of Aphrophora Goudoti. The communication made to the Zoological Society, of which a full abstract is given at the page quoted, was apparently identical with that read before the Mauritius Society.

The remaining zoological communication related to the Intestinal Worms, and was made by the Secretary. It gave some account of the Distoma hepaticum, Cuv., as found in the stomach of a cow; and of the Cysticercus Cellulose, Brems., existing in innumerable quantities over almost the whole of the head, trunk, and extremities of

a sow.

An "Extrait du Cinquième Rapport Annuel" of the same Society, by M. Julien Desjardins, Corr. Memb. Z. S., was also read.

In the year of which the present Report gives an account, M. Desjardins has communicated to the Natural History Society of the Mauritius, a list of several species of Birds that are occasional visitors of that island; and has also referred particularly to the Coturnix Sinensis, Cuv., and the Nectarinia Borbonica, Ill., as stationary in the Mauritius.

M. E. Liénard has brought from the Seychelles a species of Gecko of considerable size; which he has described in a communication made to the Society: and M. E. Liénard has placed on record the existence in the adjacent seas of the Sphargis coriaceus, Merr.

M. Liénard, the elder, has again made numerous contributions to ichthyology. He has given a detailed description of the Squalus Vulpes, Linn.: has described as new a Trichiurus, Linn., which he