is a very general feeder, and may be found on a considerable number of trees and plants. It is quite common, and but for its curious form, would certainly be found much more frequently than is the case. The perfect insect appears about July, and can be beaten out of bushes and hedges. Though the wings are large, they are thin and not very powerful, so that there is no difficulty in capturing the insect."

Of course much of the book consists of more interesting matter than this, but hundreds of pages are filled with such verbose and meagre passages as those quoted, which are far more repulsive to the learner than the most condensed and technical description. Those given in Stainton's Manual, for instance, contain more than double the actual information in about one fourth of the space.

The book is illustrated by copious woodcuts in the letterpress and by several whole-page pictures. The former are most admirable, and do great credit to the artist, Mr. E. A. Smith. We select a group of Water Beetles (Cut vi.), and one of the minute and curious parasitic Hymenoptera (Cut xxxii.) as examples of these excellent figures, which would do credit to a far more scientific work. The whole-page illustrations are by another hand, and are in every respect inferior. Some of them contain fair representations of insects in their haunts, but the vegetation is generally badly drawn, and the plants said to be figured are often quite unrecognisable. The best and most artistic picture is Plate VIII., representing a group of Neuroptera with aquatic vegetation. The worst is Plate XIX., representing aquatic Heteroptera. The insects are pretty well drawn, but the plants are dreadful. One of them is said to be the Starwort (Aster tripolium). What is meant for this stands prominently out in the view; but the artist has evidently never seen the plant, and, trusting to his imagination to invent something suited to the name, has perched three thick six-rayed starfish on bending stalks. We venture to assert that no plant having the faintest resemblance to this monstrosity forms part of the British flora, and its introduction into a modern work on natural history is most discreditable. It is painful to have to speak in these terms of the work of an author who has done so much to popularise natural history as Mr. Wood, but we must protest against mere book-making; and in this case there could be no pretence of a want to be supplied, since the excellent series of "Introductions" published by Messrs. Reeve and the more general works of Prof. Duncan, Dr. Packard, and others, are far better guides to the student or to the general reader than such a hasty and imperfect compilation as the present volume. A. R. W.

NOTES

THE Council of the Royal Society have awarded the medals in their gift for the present year as follows:- The Copley Medal, to Julius Robert Mayer, of Heilbronn; the Royal Medals to Mr. George Busk, F. R.S., and Dr. John Stenhouse, F. R. S.

testing their instruments and preparing themselves in every possible way for rapid yet correct observations during the few minutes over which the phenomena of the morning of the 12th December will extend. The Mirzapore commenced steering through the canal at 2.30 on the 8th, and anchored in Suez

Roadstead at twelve on the 10th, all well.

It was hoped that

she might sail by daylight on the morning of Sunday, the 12th. In that case she might get to Galle by the 25th, and the Expedition would then have seventeen days at their disposal for arranging themselves and their instruments over the line of totality, from the north of Ceylon to the western shore of Southern India. The passage through the Canal has been a pleasant and interesting one.

THE Falconer Memorial Fellowship, at the University of Edinburgh, which is of the annual value of about 100/., tenable for two years, has been conferred on Mr. William Stirling, B.Sc. The Baxter Physical Science Scholarship, vacant by the appointment of Mr. William Stirling, to the Falconer Memorial Fellowship, has been conferred for one year on Mr. Alexander Hodgkinson.

MR. P. L. SIMMONDS is now delivering at the London Institution, Finsbury Circus, the Travers Course for 1871-2, on Science and Commerce, illustrated by the raw materials of our manufactures, in two lectures, the first of which will be this evening, and the second on November 30th.

PROF. PARTRIDGE commenced his annual course of lectures

on Anatomy to the pupils and Royal Academicians in the new theatre at Burlington House on Monday last week, and will continue the same every Monday evening up to December 11 inclusive, at eight o'clock.

AMONG the disastrous results of the recent fire at Chicago, one not referred to in the public papers was, we regret to learn from Harper's Weekly, the entire destruction of the building and collections of the Academy of Sciences of that city. This institution, first started by the energy of the late Mr. Robert Kennicott, and carried to its late condition of prosperity under the charge of Dr. William Stimpson, had already taken a front rank among the learned establishments of the country. Its publications embraced material of the utmost value, while its museum ranked at least as high as the fifth in the United States. Although believed to be fire-proof, the building, like others of the same character in Chicago, presented but little resistance to the flames, and everything within the walls was destroyed. The loss included, besides the collections in natural history of the Academy, a large number of marine invertebrates belonging to the Smithsonian Institution, which had been forwarded to Dr. Stimpson for investigation. The private cabinet of this gentleman, and a large mass of valuable manuscript belonging to him, embracing extended memoirs upon the mollusca, radiata, and crustacea of North America, with numerous illustrations, were entirely destroyed.

AFTER a seven years' tour of exploration in South America, Dr. A. Habel, a former resident of Hastings-on-the-Hudson, has returned to New York, where he is assiduously engaged in preparing the results of his labours for the press.

Among the

FROM the English Government Eclipse Expedition we learn that since leaving Malta, on the evening of Saturday the 4th, the weather has been all that could be wished, and that Mr. Lockyer and the other members of the expedition have not failed to take all possible advantage of the calm weather in

part of Central America, the Cordilleras of the Andes in Colombia, Ecuador, and Peru, and finally the Chincha Islands and the Galapagos. During this whole period Dr. Habel was diligently occupied in gathering information in regard to the natural and physical history of the countries mentioned, especially in the departments of ethnology, meteorology, and zoology. He has already made some communications on the subject of his travels to the Academy of Sciences at Paris, and other learned bodies, and we look forward to his detailed report with anticipations of

THE new edition of Gauss's "Motus Corporum Coelestium," which has just been published by Perthes, in Gotha, and which is designated as the seventh volume of Gauss's works, and is accompanied by a copy of the original vignette, might easily seem to be a part of the edition of Gauss's works, prepared by the Royal Society of Sciences in Göttingen. We are informed by that Society that the designation of this book as "Gauss's Works, vol. vii.," was chosen without their consent, and that it forms no part of the complete edition of Gauss's works, edited by the Royal Society, and now in the press.

WE are requested by Mr. R. A. Proctor to correct a slight error in the description of Mr. Brothers' negative of his star-chart given last week. The 8-inch negatives, like the 11-inch pictures, are copies of a chart containing upwards of 324,000 stars (not 50,000 only). Prof. Airy, at the last meeting of the Astronomical Society, remarked that the constellations in this chart are not conspicuous. They could not be so, without spoiling the chart; but the lithographic key-map practically removes the objection. The chart is a contribution to physical astronomy-not intended to aid the search for individual stars, though useful in the Observatory, as showing where the richer star-fields are.

MR. THOS. J. BOYD has reprinted his paper, "Educational Hospital Reform: The Scheme of the Edinburgh Merchant Company," presented to the Statistical Section at the recent meeting of the British Association.

A SERIES of "penny lectures for working men in connection with the Museum of the Folkestone Natural History Society was commenced last week. The series is intended to illus trate the specimens in the museum-the subject of the first by the hon. secretary, Mr. Ullyett, being "Our Chalk Hills and their Fossils." If the experiment succeeds the lectures will be continued fortnightly during the winter months. Classes in botany and geology, also under the direction of the energetic secretary, were commenced on Wednesday, the 8th inst.

WF are glad to learn that the interesting series of popular science lectures, to which the charge of admission is only one penny, have been recommenced this winter session in Manchester. The opening lecture was delivered by Prof. Huxley on "Yeast," before a large and attentive audience. PE

THE Echo Agricole complains of the neglect of instruction in science in France. "Why," says this journal, complaining of the importance attached in most schools to a semi-mythological teaching, "when an intelligence is just opening to the light, should it be led through the delusive labyrinths of the marvellous, instead of showing it the truth in all its splendour? Let the young intelligence be accustomed to the observation of natural phenomena, and it will be seen to develop itself normally, because to all the branches of activity which it is called upon to exercise it will bring the spirit of methodical order which it will have been obliged to employ in the study of nature. We therefore demand that the Minister of Public Instruction should introduce into our primary schools the elementary teaching of natural science applied to what children see daily in the country. M. Jules Simon has ordered that a geographical class should be held every fortnight in the colleges and lycées; now we would have the Minister complete this measure by requiring the students not only to mention the principal products of such and such a country, but, as regards France especially, to take account of the natural produce of the land, and to know what sort of soil these different products affect. This would be geography applied to agriculture. . . . Further, we would require that all sciences relating to agriculture taught in the lycées and colleges should be followed by practical application to the soil, such experiments to form the basis of special examinations."

A DISCOVERY has been made by several farmers on the Loddon River in South Australia, that kangaroo rats are good thistle eradicators. "It has been found," says the Bendigo Independent, "that these animals dig down under the thistles, and eat the roots of the plants, which thus necessarily die. One farmer has issued orders that no kangaroo rats are to be killed on his land, in consequence of their having been of much service to him in destroying the obnoxious thistles."

Ar a meeting of the Philosophical Society of Christchurch, | New Zealand, in August last, the President, Dr. Haast, made a few observations on some moa eggs recently received from the Colonial Museum, in comparison with those of living birds. The i various models of eggs were displayed on the table. The President said that the first egg to which he would desire to draw their attention was one the pieces of which had been discovered by the Hon. Walter Mantell, and by him reunited after much labour. The original egg, from which a model had been taken by Dr. Hector, was in the British Museum. The second model was that of the largest egg found. It had been discovered in the Kaikoras Peninsula, between the legs of a human skeleton, which had been buried in a sitting position, and, from the fact of it having been so found, he argued that the moa was of great antiquity, as there was no mention in the very earliest Maori traditions of such a mode of burial being adopted. The egg was afterwards exhibited at the Otago Exhibition, and the model had been made by Dr. Hector from measurements taken by him. The third and last model was that of a small egg now in the Colonial Museum, which had been found in Otago, and which had in it the bones of a moa chick.

ON the 17th of September the installation of the Academy of Natural Science took place at Bogota, in Columbia or New Granada, with much eremony. As yet not much can be expected from it, but it is another sign of the progress taking The orator gratefully commemorated what place in the country had been done for olumbia by Humboldt, Boussingault, and Acosta in geology, and by Mutis and Caldes in botany.

THE first meeting of the Eastbourne Natural History Society for the present season was held on Friday, October 20. A paper "On the species of Hepaticæ found in the Eastbourne District" was read by Mr. F. C. S. Roper, F.L. S., containing notes on the structure and development of the group, with a list of the species (fifteen in number) occurring in the neighbourhood. It was "On the Bones of Red Deer, &c., found in followed by a paper Eastbourne," by Mr. S. Eveshed. We are glad to observe that active local work is a prominent feature of this young society.

THE Whitechapel Foundation School Literary and Scientific Society held its first annual public meeting last week in the School-room, Leman Street. The Chairman, Mr. Edmund Hay Currie, member of the London School Board, having briefly referred to the importance of the work, and to the dissemination of scientific knowledge by the society's agency, called upon the hon. secretary to read the report; from this we gleaned that the association had made good progress during its first year of existence, and that the interest in the undertaking was rapidly increasing. Twenty-six lectures had been delivered, amongs the principal subjects were 'Oxygen and Hydrogen," by Mr. Joseph Loane, M. R. C.S,, L.S.A., &c., &c., "Blood and its Constituents," and " Respiration, with its Mechanism," by Mr. H. A. A. Nicholls, of St. Bartholomew Hospital; "The Solar System," "Heat," "Coal and its products," "Electricity," ""Chemical affinity," "Water," &c., &c. The evening's proceedings were brought to a termination with a lecture on "Light," illustrated by experiments, by the President, Mr. Charles Judd. We are glad to find that this society has received considerable recognition from gentlemen interested in science and in education generally.

COLDING ON THE LAWS OF CURRENTS IN ORDINARY CONDUITS AND IN THE SEA

[I SEND to NATURE for translation the abstract (in French) appended, according to a most excellent custom, to Colding's great paper in the Copenhagen Transactions. The subject is one of especial interest at the present time, though, of course, everything written by such a man is deserving of careful attention. Those in particular who met the genial Dane at the British Association will be glad to have in a compact form his views on a question which has given rise to much discussion, and which is of very great practical importance.-P. G. Tait]

I

PRESENTED in 1863 to the Scientific Society, and some months later to the Congress of Scandinavian Naturalists at Stockholm, a short exposition of my researches on the motion of fluid bodies, on which I had been occupied for several years, and the results of which appeared to me worthy of being submitted to the Society.

The characteristic of this work is that it does not suppose, like previous works of the same kind, that all the parts of a current are endowed with the same rapidity; for it owes, in fact, its existence to my conviction that this mode of looking at the subject can only lead in exceptional cases to exact results. My researches are based on the different motions assumed by the liquid threads or elements of the currents, and are supported by the well-known fact that any body, and consequently any portion of a fluid, can only move with a constant rapidity when the accelerating force is equal to the resistance.

In the case of a fluid flowing by virtue of its own weight over a plane surface which opposes a resistance to the motion of the water, it was easy to determine how this motion varies with the depth, when the rapidity of the current is constant in all its parts; and, by pursuing this train of thought, I was led to the law of the variation of the rapidity with the depth, when the current moves in a cylindrical conduit with circular section, completely filled with the liquid. These researches are of greater interest from the circumstance that the laws at which I have in this manner arrived from theoretical considerations, are confirmed by the experiments which have recently been carried out in France by Capt. Boileau and Inspector General Darcy. These laws of the motion of water may be expressed by the formula

x,

h

7

the fall per foot of the water, and K2 a magnitude which depends entirely on the nature and dimensions of the conduit, on the depth of the current, &c. The theory shows besides that the laws of the motion of water on a level surface are in

cluded in the general law of the motion of water on a cylindrical surface, when the radius of the cylinder is supposed infinite. Darcy, who has experimentally established the formula given above for cylindrical conduits, endeavoured, at the same time, to determine K2 by means of certain experiments performed with four different kinds of pipes, and found that K2 was inversely proportional to the square of the radius of the conduit. It resulted, according to the theory, that, for level conduits, K2 should be in the same manner in an inverse ratio to the square of the depth of the current. But two series of experiments performed by Boileau with level conduits led, on the contrary, to the supposition that K2 was inversely proportional simply to the depth of the current. There was thus a want of agreement between the results of the two experiments, and the point was to discover which of these two hypotheses was correct. Several circumstances leading me to believe that Darcy's theory could not be exact, I took as my starting point the experiments of Boileau, and considered K2 as inversely proportional to the depth of the current, which I did with the less scruple since this hypothesis agreed almost as well with Darcy's experiments as with his own. I pursued, therefore, my researches on this basis, and, after many difficulties, arrived at results which, on the whole, were so entirely in accordance with experiments that I could not suppose the possibility of Boileau's hypothesis being inexact. only afterwards, when I approached the study of marine currents, that new difficulties constantly arose, which I endeavoured at first to overcome, but which became day by day more insur

It was

mountable, until at last there was nothing left but to doubt the correctness of my calculations, since they led to results which were in obvious contradiction to facts.

The theory then was shown to be inexact; but since in so large a number of cases it was evidently in agreement with experiment, I attempted by a variety of means to discover the error which I must have committed; still all my attempts were unattended with result, and I was on the point of abandoning the resolution of the problem to which I had already devoted so much time, when the idea struck me of examining what would happen if I rejected Boileau's determination of A2, and adopted Darcy's hypothesis, although it still appeared to me impossible; when I found, with as much delight as surprise, that it removed not only the great difficulties which I had up to that time encountered, but also all the contradictions which had occurred to me as an inevitable consequence of that hypothesis, and from that moment the results of the calculations showed themselves to be entirely in the most perfect accordance with what exists in

nature.

I

The circumstance that the experiments of Darcy are almost as satisfactory whether is supposed to be proportional to the K2 first or to the second power of the depth of the currents, made me think that the reality would be still more nearly approached by expressing this magnitude by a binomial of the first and second degree, and this was completely confirmed by facts. In determining the constants of the binomial according to the results of Darcy's experiments, I found the law of the motion of the water in cylindrical pipes with a radius R, with a coefficient of resistance m, and a rapidity 2, at the surface of the conduit, may be represented by the formula

This formula shows, among other things, that the ratio which corresponds to any point in a given conduit entirely filled by the current, is entirely independent of the rapidity of the current, a fact which Darcy's experiments confirm in a remarkable manner. This relation furnishes us besides with the means of determining the value of the coefficient of resistance m for different kinds of pipes which were employed by Darcy, and it is thus found that for

New varnished pipes. m values which

of the conduit.

=

are altogether independent of the diameter For level wooden couduits, it is found, according to the experiments of Boileau, that m = 00160 to

o'0090, while the resistance of the air, according to the same author, corresponds to m = 30'0003 to 0.0002

Inspector-General Darcy has unfortunately died, but the researches on currents which he commenced were continued by the French engineer Bazin, who published in 1865 a great work with conduits of very different kinds. on the results of a considerable number of experiments carried on

However interesting otherwise these researches may be, they do not display either the powers of observation or the grandeur of conception which distinguish the works of Darcy. Among those experiments which are of the greatest interest, there are some begun by Darcy and finished by Bazin, such as researches into the motion of water in rectangular conduits, where the rapidity is determined in 45 points symmetrically distributed. The result is indepen

for these, as for circular conduits, is that the ratio

ย

V

dent of the absolute rapidity of the current, and if the results of experiment on the motion of water in level conduits are compared with those given by the theoretic formule, it will be found that these last agree so completely with experiment, that the difference between the calculated and observed rapidities, in each of the 45 points mentioned above, falls within the limit of errors of observation. This agreement is especially remarkable in the case of the conduit which Darcy employed in 1857 for the carrying out