254 



♦ KNOWLEDGE 



[April 27, 1883. 



LAUGK SUN-SPOT. 



[7n6]— Abont six o'clock, April 3, I glanced at the nun as ho 

 was ncariiii? the western horizon, and as there was a little mist 

 about the horizon, which made it easy to look at him with the 

 naked eye, I could distinctly see a black spot a little to the right of 

 the centre. I called tho attention of two friends to it, and they 

 also saw it qnite easily. 



On Saturday and Sunday following I obscrred the sun with my 

 telescope, and then jierceived one rather large spot and several 

 smaller ones, and on the latter day I showed them to my wife and 

 several friends, and remarke<l to them that I believed that if we 

 could got a naked-eye view of the sun, wo should be able to see 

 the larger spot, and so that opinion has been eonlirmed since. 



Seen through the telescope, it was triangular shaped, the central 

 black part, or umbra, being all in one, and not divided into several, 

 as was tho case in the great spot seen last November. 



EXCELSIOE. 



A subscriber, F.U.A.S., sends ns this picture of tho large sunspot. 



" 1 



April 15, 9.30 a.m. (with -tin. power 96 Eamsden). 



[Our correspondent retoarks on the " peculiar series of little 

 bridges in one of the spots." " I watched them carefully," he 

 writes, " for fully half an hour, and there seemed a most violent 

 action going on around each bridge ; so much bo, that 1 contemplated 

 a violent disruption and equalisation of the whole mass into one 

 chasm. The whole spot seemed ' all alive,' whilst the smaller ones 

 were passive. Towards the close of the half-hour, the right-hand 

 large spot seemed to wake up, and numerous indentations became 

 manifest. After a while, the undulations seemed to settle down 

 as I drew them, and after that a more peaceful state seemed to 

 reign."] 



SATURN'S RINGS. 

 [797]^Mr. Ward points out (775), an objection to Professor 

 Adams's theory about Balle's figure of Saturn in '■ Phil. Trans.," 

 which appears to me fatal to that theory. Professor Adams, indeed, 

 foreseeing the objection, is forced to have recourse to the rather 

 lame expedient of supposing that the clause about tho notches 

 quoted from Balle " has been added or altered in some way " 

 (Monthly Notices, R.A.S., Vol. XLIll., No. 3, p. 94). But there is 

 an additional reason, not yet pointed out, for thinking that the 

 indentations in the figure were intentional. 



In his paper, read before the lloyal Astronomical Society, and 

 quoted above, i'rofessor Adams says, " The paper was first folded 

 twice in directions at right angles to each other, so that only a 

 quadrant of the ellipse had to bo cut." Now, I have carefully ex- 

 amined the original cutting with a magnifying- glass, and I am pre- 

 pared to say that, while there is a very distinct perpendicular fold, 

 there is not the slightest trace of any horizontal fold. This may, 

 at first sight, appear to be unimportant, but it is important — in this 

 way : — It the paper had been folded in four, one cut would have 

 made both notches, and there would have been only one mishap. 

 But being folded in two, it follows that Balle made the same mis- 

 take (?) twice over, first in beginning the cut, and secondly in end- 

 ing it. As a confirmation of the objection brought forward by Mr. 

 Ward, I think this is not altogether unimportant. 



Tho B.^tisfactory thing would bo to find Balle's letter. We should 

 then know whether tlie cutting was his own, or whether (what is 

 very possible) it was merely made by Oldenburgh from a drawing in 

 Balle's letter. I have made every search, however, in the archives 

 of tho Royal Society, and I am tolerably certain that neither the 

 original nor any copy of the letter remains there. It was probably 

 returned to Sir H. Moray as soon as Oldenburgh had done with it. 



Scionco Club, Savile-row, W. IIekukkt Rix. 



SUN AND MOON OF GIBKON. 



[798]- — As you cannot forward my letter to Mr. Garbett, for want 

 of his address, I wish to say that in it I expressed the fact that the 

 LXX. version does not seem to bear out his rendering, " Bo thou 

 silent," though the margin gives this as the Hebrew. I am not an 

 Hcbraid, but these translators would surely not have used Triyrw, 

 and iv araait, and tdTrj, if they had understood it bore the sense 

 Mr. G. would put on it, whatever the physical fact may have 

 been. A different Greek verb is that " to keep silence," — aiyau, I 

 do not know whether you would admit a theoexegetical discoSBion 

 in your columns, which are not intended for such. Mr. Garbett 

 (|uotes Bryant as an authority, but 1 do not think he is much 

 thought of in these days of modern research. II. M. W. 



[The Septuagint is not a very excellent translation. In English, 

 " Be thou still" would be near the mark, as conveying the actual 

 force of the Hebrew, which may mean either " be silent," or " stay 

 still."— R. P.] 



A PHENOMENON. 



[799] — I am afraid I am rather late in mentioning a peculiar 

 phenomenon I observed some time ago, and which no one could ex- 

 plain to me. On April 5, at about 5.20 p.m., at Wimborne, in Dorset, 

 while out on a hill near there, I chanced to look up at the sun, 

 when I observed at a distance from that body of about twenty 

 times his diameter, or perhaps a little more (1 cannot give the 

 distance astronomically), at the same distance above the horizon 

 as he was, a small piece of rainbow. This was to tlie west of the 

 sun ; it was about twice his diameter in length, and stood verti- 

 cally, as though part of a large rainbow-like halo. There were no 

 clouds about, but only a sort of cloudy haze, which was neither cloud 

 nor haze, and had no definite edge, but gradually melted into the clear 

 sky some distance above the horizon. The sun and rainbow were 

 just within this haze, where it was appreciably thick. No rain 

 came after, nor could I hear of any having fallen at that time 

 anywhere about the district; and, besides, I was not between it 

 and the sun, but both were before me. Several other persons 

 observed it; one was with me, and plenty more mentioned it to me 

 afterwards, but none could account for it. Hoping (if it be not 

 too late) to see an explanation soon, Imperitus. 



April 18. 



[Undoubtedly part of a solar halo; in other words, formed by 

 refraction of sun's light through ice-prisms. — R.P.] 



FLOURY AGAINST WAXY POTATOES. 



[SOO] — lam much obliged to "E. W. P." for his suggestions 

 (783) regarding the difference between a waxy and floury potato- 

 They are in strict accordance with my own belief, but in jiractice I 

 find great difficulty in growing the quality desired, for I often find 

 floury potatoes produced on land rich in nitrogen, more especially 

 if slow of decomposition ; whereas land poor in nitrogren may — for 

 instance, in a sunless, wet year — have very waxy roots ; so that I 

 presume sunlight or rain has as much as manuring to do with it. 



With Dr. H. Muller's investigations I have been acquainted for 

 some time, but, from some known facts, I think many of his 

 deductions will require confirmation before being accepted as 

 truths. For instance, every farmer knows that even after the 

 severest winters his plough in the spring turns up many potatoes 

 in nice fresh condition, from only a few inches deep. These roots 

 must have been frozen through for days, and even weeks, together, 

 and yet kept qnite sound. 



It is also known that potatoes frozen, or believed to be frozen, in 

 the drill, pet, or clamp, will in many cases turn out little the 

 worse if let alone till the frost is some time off, whereas if imme- 

 diately removed, nearly all will be wasted. 



In my experiments tho ashes used were fine coal cinders from 

 nnder the engine furnace, and both lots of potatoes were removed 

 from the place where frozen at the time and immediately cooked. 



Fabhes. 



SINGLE EYE-GLASSES. 



[801]— Mr. Kling, in his letter. No. 788, on " Single Eye-glasses," 

 seems to me to miss the obvious meaning of the author of " How 

 to Use the Ej'es." I take it that the meaning of the passage is 

 that single glasses are of themselves hurtful, whether they help the 

 wearer to see better, or are worn for a less worthy purpose. 



I think tho discussion as to the benefit of spectacles with lenses 

 of different powers must have been quite set at rest, for a year or 

 two ago I had to take to spectacles, and was ordered by a surgeon 

 to one of the ophthalmic hospitals to obtain a pair of unequal 

 strength. I should imagine that in case one eye is weaker than 



