Sept, 5, 1878] 



NATURE 



495 



■water po\Yer ; whereas storage below ground, excepting 

 tanks, remains for the engineer of the future. 



Since, then, the agricultural interest is an irresponsible 

 flood producer, and makes no counter provision for the 

 storage of the water prematurely taken out of the soil ; and 

 since existing Conservancy Boards have not the neces- 

 sary powers to deal with floods ; and since the claims of 

 water supply are paramount, and, from being strongest in 

 periods of drought, can only be met by provision from 

 flood waters ; and since again many of the subterranean 

 water-systems are being steadily exhausted, it becomes 

 evident that no existing authority has the powers neces- 

 sary for the successful treatment of the various questions 

 so intenvoven. 



Whatever shape or shapes this governing body may 

 ultimately take, all authorities who have expressed their 

 views upon these questions are agreed that a preliminary 

 survey of the natural sources of supply is necessary. The 

 collection of these essential premises to successful legis- 

 lation and to successful engineering works lies within the 

 special province of hydrogeology, which takes up the 

 history of rain-water from the time that it touches the 

 soil. The tangible product of the survey is a map, which 

 shows at a glance the necessities and the capabilities of 

 each river basin. By the execution of such a map and 

 the mere exhibition of the facts, a great stimulus is given 

 to engineering enterprise, and by the establishment of 

 such a survey, as a forerunner to legislation encouraging 

 the construction of all necessary works, and the conse- 

 quent removal of the feeling of want of scope that has 

 stood in the way of the engineer hitherto. Government 

 will have earned the thanks of the engineering profession 

 and of the nation at large. Joseph Lucas 



THE INTRA-MERCURIAL PLANET 



V^TE publish the following three communications in 

 ' * reference to the observations and calculations 

 of Prof. Watson on the intra-Mercurial planet, about the 

 existence of which there now seems little doubt. It will 

 be seen from the third communication that Prof. Watson 

 has been led to slightly alter the place of the planet from 

 that given in the foot-note to Mr. Lockyer's article last 

 week. 



Prof, Watson, it will be remarked, refers to a second 

 object, which he considers probably new. The position 

 of the nearest conspicuous star f Cancri, at the time of 

 his observation, was in R.A. 8h. $m.. 14s. '4, and dechna- 

 tion 18° o'-g. 



The following letter to Mr. Lockyer we referred to in 

 the foot-note (p. 462) last week : — 



" University 0/ Michigan, Observatory, Attn Arbor, 



"August 14, 1878 



" Since my return I have placed the paper circles on a 

 graduated circle, and have read off the marks made 

 during the observations at Separation. The resulting 

 place of Vulcan differs slightly from that which I inferred 

 from mere estimation at the time of the observations. 



" The place which I have now derived I consider to 

 be trustworthy within 5' of arc. It is as follows : — 



Washington Mean Time. R.A. Dec. 



1878, July 29 ... 5h. i6m. ... 8h. 26m. 54s. + 18° 16'. 



" You are already famihar with the method which I 

 adopted. If I were to do the work over again I would 

 use the same method. It does not give the place so 

 accurately as it would have been given by graduated 

 circles and verniers, but it does away entirely with the 

 uncertainty which might be attributed to an erroneous 

 circle reading at the time. My circles are like the chro- 

 nographic record of a star transit. They give the 

 pointings for the planet and the sun, and the readings 

 can now be made at will. 



" You will be pleased to hear that the planet was seen 

 a few minutes afterwards by Mr. Lewis Swift, who ob- 

 served in the neighbourhood of Denver. Mr. Swift is 

 known to astronomers by his discovery of comets. I do 

 not know whether he obtained anything more than an 

 estimate of the position ; but the place in which it is 

 reported that he saw the planet agrees with my obserra- 

 tion. This corroboration is peculiarly fortunate, con- 

 sidering the negative results of other observers. 



"James C. Watson." 



The following has been forwarded to us for publication 

 by the Astronomer- Royal : — 



" Keswick, September 2, 1878 

 " I have received from Prof. James C. Watson the fol- 

 lowing communication in reference to the suspected intra- 

 Mercurial planet : — 



" * University of Michigan, Observatory, Ann Arbor 



'''August 14, 1878 



" ' During the recent total eclipse of the sun, I devoted 

 myself to a search for an intra-Mercurial planet. In 

 order to expedite the record of position, I placed disks of 

 cardboard on the circles of the equatoreal, and marked 

 the pointings by means of a sharp pencil and a pointer. 

 All danger of error from wrong circle-readings is in this 

 way avoided. 



'"In the course of the search, I came across a ruddy 

 star of the 4^ magnitude, which had a perceptible disk, 

 the magnifying power being only 45, and which was in a 

 position where there is no known star. It was very much 

 brighter than Q Cancri, which was seen a little further to 

 the west. Its position was referred, by means of the 

 circles, to the sun, and was as follows : — 



Washington Mean Time. 

 1878, July 29 5h. i6ni. 



Apparent a. 

 8h. 26m. 54s. 



Apparent h. 

 + 18° 16' 



" ' There was no appearance of elongation such as 

 might be expected if it were a comet, and hence I feel 

 warranted in believing it to be an intra-Mercurial planet 

 The details of the observations I will send you hereafter.' 



" Prof. Watson's statement appears to render it very 

 highly probable that the object seen is really an intra- 

 Mercurial planet. I remark, however, that the reason 

 for excluding the supposition of its possible cometary 

 character does not seem quite conclusive, as, when the 

 tail of a comet and the small appendages of its head are 

 invisible, the nucleus is usually circular. 



"G. B. Airy" 



The following letter to Mr. Lockyer, just received, con- 

 tains Prof. Watson's latest statement on the subject : — 



" Uttiversity 0/ Michigan, Observatory , Ann Arbor, 



" August 7.2, 1878 



" On account of a wrong value of the correction to be 

 applied to Prof. Newcomb's chronometer, the place of 

 the new star which I communicated to you last week was 

 erroneous. Please substitute, in place of the numbers 

 then given, the following : — 



Planet - 

 Aa AS 



— Sm. 2IS. - 0° 22' 



Washington Mean Time. 

 S, July 29 5h. i6m. 37s. 



Planet's Apparent. 



S 

 + 18° 16'. 



St. 27m. 35s. 



"The more I consider the case the more improbable it 

 seems to me that the second star which I observed and 

 thought might be i Cancri, was that known star. I was 

 not certain in this case whether the wind had disturbed 

 the telescope or not. As it had not done so in the case 

 of any other of six pointings which I recorded, it seems 



