i66 



NA TURE 



[Dec. 30, 1875 



OUR BOOK SHELF 



A Monograph of the TrogonidcB ; or, Family of Trog;ons. 

 By John Gould, F.R.S., &c. (London : Published by 

 the Author, 1875.) 



The completion of a second edition of Mr. Gould's 

 " Monograph of the Trogons," is an event which ought 

 not to pass by without a notice in this Journal. The first 

 edition of this work, published in 1838, was one of the 

 earliest of Mr. Gould's magnificent series. Of its fellow 

 Monograph, that of the Toucans, a second edition was 

 issued some time since, and the present work is a worthy 

 companion to it. During the thirty-seven years which 

 have elapsed since the publication of the first edition of 

 the " Monograph of Trogons," Mr. Gould, as his brother 

 ornithologists know full well, has by no means neglected 

 the subject, but has from time to time brought forward 

 descriptions of new species that have come to his know- 

 ledge from the more thorough exploration of the tropics 

 that has of late years taken place. From these, and 

 other sources, the number of known Trogons, which at 

 the time of the first Monograph was thirty-four only, has 

 now been increased to forty-six, of the whole of which 

 splendid life-sized pictures, according to Mr. Gould's 

 wonted practice, aie given in the present volume. 



Like the Parrots, the Trogons are widely diffused 

 through the tropics of both hemispheres. Though not so 

 strongly marked in general characters as the Psittacida^ 

 the TrogonidcC are separated from all other known birds 

 by the peculiar conformation of their feet, having the 

 first and second toes permanently turned backwards, 

 which is not the case in any other form of the class 

 " Aves." Like the Parrots, too, the Trogons are most 

 numerous in the New World, thirty-three out of the forty- 

 six species being peculiar to Central and Southern 

 America, whilst eleven are found in the Indian region, 

 and two only in Africa. As regards habits and mode of 

 life, there appears to be much similarity in the Trogons 

 of all three continents. They are universally forest- 

 haunting birds, inactive in habits, short in flight and 

 feeding, whether their prey be insect or fruit, mostly 

 upon the wing. Their brilliant colours offer the most 

 remarkable compounds of emerald green and various 

 shades of crimson and golden yellow, as will be suffi- 

 ciently apparent to anyone who turns over Mr. Gould's 

 splendidly-coloured plates. We must indeed congratu- 

 late the author on the energy and success with which, 

 prompted by the pure love of science, he has brought out 

 a second edition of one of the first of his many important 

 ornithological works. 



Geolo^ie der Kohletilager, von Dr. Hermann Mietzsch, 

 Geolog der Landesuntersuchung im Konigreiche Sach- 

 sen. (Leipzig, 1875). 



For those to whom the magnificent work of Geinitz, 

 Fleck, and Hartig, Die Steinkohlen Deutschlaitds, is inac- 

 cessible, the smaller treatise before us will prove accept- 

 able. From the practical acquaintance of his subject 

 gained in his professional duties. Dr. H. Mietzsch was 

 well fitted to produce a treatise on the physical properties 

 of coal and the phenomena connected with its place 

 amongst the strata ; while, with the industry which gene- 

 rally characterises German authors, he has made himself 

 acquainted with what has been written on the subject by 

 French and English writers, as well as those of his own 

 fatherland, and has woven the whole into a connected 

 account of the history of coal-mining, the properties of 

 coal, and the conditions under which it has been found in 

 various countries and peiiods, as well as the structure 

 and mode of formation of coal-fields and coal-basins. 

 The work is illustrated by twenty-five woodcuts, and 

 appears to bring the subject well up to the present state 

 of our knowledge. E. H, 



LETTERS TO THE EDITOR 



\_Tht Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers of, rejected manuscripts. 

 No notice is taken of anonymous communications.'] 



Evidences of Ancient Glaciers in Central France 



Were this a question concerning volcanic phenomena, with 

 which Mr. Scrope is as familiar as I am with glacial ones, I 

 might be disposed to defer to his opinion. As it is, having only 

 his assertion that I have mistaken the results of a recent land- 

 slip (i.e. a spot where ther. are no traces of landslip, and to which 

 no landslip could have reached) for time-worn and weathered 

 glacier-transported blocks, I ask the readers of Nature to pause 

 before disposing of my powers of observation as summarily as 

 Mr. Scrope does ; remembering that the history of all glacial 

 phenomena, from scratched boulders to lake-brsins, has been 

 successively overlooked, denied, and misinterpreted, before 

 being understood and accepted. 



The landslip to which Mr. Scrope refers, and which he de- 

 scribes as having occurred in 1859, under cliffs nearly a thousand 

 feet high "on the left flank of the valley looking upwards," is 

 in a very different position from that of the blocks to which I 

 have directed attention. There are no cliffs whatever such as 

 Mr. Scrope describes on the left flank of the valley anywhere 

 near their position, nor for half a mile above it. The left flank 

 of the valley for half a mile above them forms a very gentle 

 slope indeed, and rises but a very few hundred feet above its 

 floor, without cliff or rock protruding on its surface. 



On the other hand, the evidences of old ice action in the Mont 

 Dore district, and elsewhere in Central France, are as conclu- 

 sive as in Western Scotland, M. I'Abbe Lecoq notwithstand- 

 ing, for whose labour in his own line of research I have as high 

 a regard as I have for Mr. Scrope's. 



J. D. Hooker 



Sir Thomas Millington and the Sexuality of Plants 



The letter of your anonymous correspondent "A. B. C," in 

 your issue for DcC. 16, hardly seems to need a reply, inasmuch 

 as he has added nothing whatever to the solution of the question 

 raised in mine, whether any writings of Sir Thomas Millmgton 

 are in existence which confirm the alleged discovery by him of 

 the sexuality of plants. From the silence of your correspondent 

 on this point, as well as of the two writers referred to in my 

 letter, I infer that no such writings are, at all events, readily 

 accessible. There are, however, some statements by your cor- 

 respondent which cannot be allowed to pass uncorrected. 



First, as to the bibhographical matter : " A. B. C." says " there 

 is no such thing" as a second edition of Crew's book — a some- 

 what rash assertion in the face of the fact that the words " The 

 2nd edition " are printed on the title-pages of three out of the 

 four books which make up " The Anatomy of Plants," first pub- 

 lished as a whole in 1682. The facts of the case are these : In 

 1672 Crew published a small volume under the title " The 

 Anatomy of Vegetables begun, with a general Account of Vege- 

 tation founded thereon;" in 1682, a much larger work entitled 

 " The Anatomy of Plants begun, wi'h a general Account of 

 Vegetation founded thereupon," a portion of which is a reprint of 

 the earlier work. I fail to see why I should be held up to re- 

 proach as having almost committed a literary crime in referring 

 to the larger as " a second edition " of the smaller work. 



Now as to the more important matter. Without bringing for- 

 ward a tittle of fresh evidence, " A. B. C." makes the confident 

 assertion that it is " also clear enough " that Millington is entitled 

 to be described as the discoverer of the sexuality of plants. In 

 singular juxtaposition with this assertion he quotes a paragraph 

 from Sprengel in which some half-dozen illustrious botanists are 

 named in this connection, but Millington is not even mentioned ! 

 The preceding quotation from Crew is made to appear as if it 

 owed its inspiration to Millington ; whereas, after the graceful 

 reference to his friend the Savilian Professor, Grew commences 

 his account with these words : — " The sum therefore of my 

 thoughts concerning this matter is as follows." It would seem 

 as if, at the close ot the seventcnth century, fresh insight into the 

 phenomena of fertilisation was being gained by a number of 

 botanists in both England and Germany; but "A. B. C." has 

 estabhshed no right to express an opinion in so ex cathedrd a style 

 in favour of Millington's sole claim to the discovery. For evidence 



