NATURE 



{Dec. 7, 1 87 1 



men is usually of the highest quahty, both for carefulness 

 of investigation and clearness of statement ; and the great 

 similarity which exists between the faunas and floras of 

 our islands and of the Scandinavian region, enables their 

 work to be used to a certain extent as handbooks by 

 British Naturalists. May their study lead the latter to 

 imitate the Scandinavian mode of work ! We are led to 

 these remarks by the receipt of the tenth and concluding 

 volume of Prof. Thomson's descriptive work on the Scan- 

 dinavian Coleoptcra, although this consists almost entirely 

 of corrections, emendations, and additions to the con- 

 tents of the nine previous volumes, in which the syste- 

 matic description of those insects was completed. Prof 

 Thomson's work will be found of the highest value to the 

 British entomologist, inasmuch as a very large proportion 

 of the insects described in it arc inhabitants of these 

 islands, and many of the others will probably be dis- 

 covered hereafter in the north of Scotland. The whole 

 descriptive portion of the book is written in Latin, the 

 characters, although often brief, are admirably drawn 

 up, and the determination of the species is greatly facili- 

 tated by the excellent tables both of genera and species 

 given throughout the work. Amended tables, introducing 

 all new forms discovered during the progress of the book, 

 are given in the second part of the ninth and in the tenth 

 volumes. Although it appears under a Swedish title, the 

 only portions of the work written in that language are the 

 notices of localities of occurrence and critical remarks on 

 genera and species, the former, at any rate, requiring little 

 knowledge of Swedish for their comprehension. W. S. D. 

 Ichneumonologia Suecica, auctore Aug. Emil Holmgren. 



Tom. II. (Stockholm, 1 87 1. London: Williams and 



Norgate.) 

 This is a second most important Swedish work, which 

 illustrates in a striking manner the remarks which wc 

 made in noticing M. Thomson's " Skandinaviens Coleop- 

 tera." In this the author has commenced a monographic 

 revision of the Swedish members of one of the most 

 difficult families of insects, the Ichneumonida;, which he 

 here treats in an almost exhaustive fashion. We cannot 

 venture to say how far he is correct in his synonymies, or 

 in the reference of supposed species toothers as varieties ; 

 but he has .spared no pains in the preparation of his de- 

 scriptions, and the student of his book will hnd no difficulty 

 in understanding precisely what he means. This work, 

 when completed, will be an invaluable aid to the few ento- 

 mologists who venture upon the study of the Ichneu- 

 monidae. W. S. D. 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. No notice is taken of anonymous 

 conimitnications. ] 



The Planet 'Venus 

 This beautiful planet being now very favourably situated for 

 examination, it may interest many of your astronomical readers 

 if I give a brief description of the markings which have recently 

 been seen on her surface. That these markings are exceedingly 

 difficult objects to detect, even with a powerful telescope and 

 under favourable atmospheric conditions, there is no doubt, and 

 many observers have consequently failed to see them. The late 

 Rev. W. R. Dawes, although possessed of very excellent vision, 

 could never make them out, and it seems that the fact of their 

 existence is doubted at the present time by some observers. At 

 the meeting of the Royal Astronomical Society on November 

 10 last, " the Astronomer Royal mentioned that Venus was very 

 favourably situated for observation, especially for noticing spots 

 if any existed on her surface, his own experience being that there 

 were no certain markings thereon, whicli the President corrobo- 

 rated." The opinions of such eminent astronomers should always 

 be carefully considered, and the matter in dispute thoroughly 

 Investigated, before a contrary opinion is entertained. In the 

 present case, however, I think that there is a suffic:c ;cy of 



evidence to prove that markings of various forms exist on the 

 surface of the planet. I am the more particularly induced to say 

 this by having before me upwards of sixty sketches of their appear- 

 ance, made by experienced observers, whi in the m.iking of ob- 

 servations employ telescopes of great power and excellent defini- 

 tion. No doubt the faint chnrllke mirkings can only be made 

 out after attentive gazing, and then are scarcely visible, though 

 they have been distincdy seen by many observers. It is difficult 

 to account for the fact that Mr. Dawes could not dist.nguish 

 them, but perhaps the reas m may be apparent, if we consider that 

 an observer who is the most successful in the observation of faint 

 companion; to double stars, cannot satisfactorily observe the 

 faint markings with which th; planet's disc is diversified. 

 Many observations of the spots were mxde at Rome in 1839 — 

 1841, and of six obstrvers those wee the most successful who 

 experienced the greatest difficulty in detecting minute com- 

 panions to large stars. * 



With respect to the spots and markings which have recently 

 been examined, it may be said that they are of various forms and 

 degrees of visibility. Some of them are only just perceptible 

 after a long and careful scrudny of the phmet's die, while others 

 are much more apparent, and distinguishable with less difficulty. 

 Whether or not they are permanent in their form remains to be 

 determined from a comparison of the whole of the observations. 

 Some of the representations of the cloudy spots taken at diflferent 

 dates seem to be somewhat similar in their principal features. 

 Several time; that position of the planet's^ surface immediately 

 adjacent to the terminator has been seen to be interspersed witu 

 small bright circular spots, which seem to be analogous to lunar 

 formations. These bright spots have been seen by several of 

 those who have critically examined the planet's appearance. 

 They were seen by Mr. T. H. Buffham on May 4 and May 6, 

 186S, and Dr Huggins at the last meeting of the RA.S.said 

 that " he had occasionally seen dusky spots, but he considers 

 them as very uncertain or illusive. When, however, the 

 crescent was thin and the planet near the earth, he had seen 

 minute points of light on the terminator, which by most ob- 

 servers was described as irregularly indented. He had also 

 noticed that when definition was very go^d, appearances analo- 

 gous to those of lunar craters had been seen. Dr. De la Rue 

 had often seen markings on Venus similar in character to those 

 observed on Mars." An observation made by Mr. F. Worthing- 

 ton, with a 13-inch reflector, on June II last, confirms the 

 statement made by Dr. Huggins in reference to the bright mark- 

 ings on Venus be'ng similar to objects on the surface of our 

 fatellite. He writes, " Definition extremely good. Themarkings 

 were very clearly seen, and bore a very remarkable resemblance 

 to the craters and inequalities of the moon as seen with a low 

 power, say an opera glass." From the foregoing it would appear 

 to be beyond a doubt" that, when the planet is in a crescent form, 

 small bright markings, resembling lunar craters, are perceptible. 

 These objects should be persislently looked for, and when 

 observed the details of their appearance anl position duly 

 registered. 



That the dark, cloud-like markings are similar to those on the 

 surface of Mars, as stated by Dr. De la Rue, seems also an 

 established fact. Mr. Henry Ormesher saw several irregular spots 

 on Venus on May 10 last, and he says they were "clear and 

 well-defined, and reminded me very much of those on the planet 

 Mars, as they had nmch the same appearance." Of course the 

 markings on Mars are much more conspicuous than those visible 

 on Venus, but in their appearance there is no doubt that they 

 are not altogether unlike. 



In many of the drawings which I have before me the outlines 

 of the cloudy patches do not terminate abruptly as in the case of 

 the penumbrx to solar spots {maciiht) but seem to fade away 

 into the general brilliancy of the disc. In some of the sketches, 

 however, the boundary of the spots appears to have a well- 

 marked outline. In regard to the terminator, it seems to have a 

 very serrated edge, but in some of the drawings this is not 

 depicted. 



Referring again to the coincidence in the appearance of the 

 bright spots of Venus and the craters of the moon, I would 

 draw the attention of your readers to the Rev. T. W. Webb's 

 "Celestial Objects," second edition, p. 51, in which there is an 

 observation of interest recorded. William F. Denning 



Hollywood Lodge, Gotham Park, Bristol, Nov. 28 



♦See Webb's "Celestial Objects," p. 50. It is there stated that " a very 

 sitive eye which would detect the spots more readily would be easily 

 rpowered by the light of a brilliant star, so as to miss a very minute one 

 its neighbourhood." 



