May 1 6, 1878] 



NATURE 



6; 



The £tructure_of Coryphodon 



I OBSERVE in your issue (vol. xvii. p. 340) a note by Prof. O. 

 C. Marsh stating that I have included in the cast of the olfactory 

 lobes of the brain of Coryphodon that of a part of the nasal 

 cavity also. Prof. Marsh fails to point out the qualifying 

 remarks to be found in my descriptions. In the explanation 

 of Plate I. of the Proceedings of the American Philosophical 

 Society, 1877, p. 620, I say, " The right bulbus of the olfac- 

 tory lobe is too large above, owing to the want of preservation 

 of the superior wall of the cavity," In my quarto report to 

 Lieut. G. M. Wheeler in Vol. IV. p. 223 of his Report to the 

 Chief of Engineers, I remark, " In excavating the matrix from 

 the Olfactory chambers some difficulty was experienced in 

 attempting to lay bare the superior and inferior walls, &c. On 

 one side of the bulb this boundary was probably passed through, 

 giving a larger vertical diameter than the true one," 



Philadelphia, March 23 E. D, Cope 



[Prof, Cope adds other remarks on thi, subject and on other 

 questions in dispute between himself and Prof. Marsh, which 

 our space will not permit us to reproduce. — Ed.] 



Lightning Phenomenon 



On observing the lightning on Friday evening I noticed that 

 several of the brighter flashes were preceded by one, or some- 

 times two smaller flashes, the large flash following immediately 

 after and taking the same coiu-se as the smaller ones. I should 

 be glad to know if any of your readers observed this, and also 

 how it is accounted for. H. J. Staples 



Clifton Collesre 



Secondary Lunar Rainbow 



At an early hour this morning I had the good fortune to wit- 

 ness a phenomenon which is of somewhat rare occiurence. 



Soon after 12.15 a.m., at which time I was burning the mid- 

 night oil, by a curious coincidence, over spectrum analysis, I was 

 roused from my books by the pattering of rain outside the open 

 windows ; upon looking up I perceived that the moon was 

 shining brightly, and naturally concluded that as it was not very 

 far above the horizon there must be a rainbow. 



I rushed over to the opposite side of the "quad." and was 

 rewarded for my wetting by the appearance of a most magnifi- 

 cent bow, in v.'hich the colours were easily distinguishable on 

 the dark background of clouds. To complete the phenomenon 

 and to render it remarkable, there was also a perfect secon- 

 dary arc. 



The primary bow lasted in great brilliance for more than ten 

 minutes, and thus I was enabled to rouse some of our men to 

 see it, but it vanished with the punctuality of a creation of a 

 fairy tale, immediately the clock tolled the half-hour. Soon 

 after its disappearance the clouds were dispersed and the heavens 

 studded with stars. W, J, Noble 



Keble College, Oxford, May 12 



OUR ASTRONOMICAL COLUMN 



The Reappearance of Tempel's Comet, 1873, 1 1- — 

 The Bulletin International of the Observatory of Paris 

 for May 7, contains the elements of this comet for the 

 return to perihelion in the present year, as determined 

 by M. Leopold Schulhof from a complete discussion of 

 the observations in 1873, and the application of the per- 

 turbations up to the next perihelion passage. Expressed 

 in a form slightly modified from that adopted in the 

 Bulletin, the elements are as follow ;• - 



Perihelion passage, 1878, September 1*4961 G.M.T. 



Longitude of perihelion ... . 

 ,, ,, ascending node 

 Inclination of the orbit ... 



Eccentricity 



Log. semi -axis major 

 Mean daily sidereal motion 



306 7 2 ) Mean Eq. 

 120 59 41 \ 1878-0. 



12 45 34 



0-552895 



0-476478 



684"-3689 



Motion— direct. 



It will be remarked that the date of perihelion passage 

 given by M. Schulhof s investigation is considerably later 

 than was assumed ina former note in this column, from 



•^he best calculation of elements at the last appearance 

 then available, and we believe it is yet open to material 

 uncertainty. The recovery of the comet at this return 

 may therefore involve a very close search with instru- 

 ments of great optical capacity, but as it may, and very 

 probably will be within reach when the moon is again 

 below the horizon in the evenings, it may be hoped that 

 no time will be lost in commencing a strict examination 

 of the track of sky on which its orbit must be projected 

 at different dates. The following positions are extracted 

 from M. Schulhof s ephemeris : — 



The intensity of light at the date of the last observation 

 of the comet in 1873, "which was made at Mr. Bishop's 

 Observatory, Twickenham, on October 20, was o"385. 

 At this time the comet was the extretnum visibile with a 

 7-inch refractor. It may appear strange that observa- 

 tions should not have been made at a later period with 

 the more powerful instruments available in many of the 

 European observatories, but it does not always occur that 

 the largest telescopes show decided advantage over much 

 smaller ones in following up faint comets. With the 

 same refractor De Vico's comet of short period of 1844 

 was distinctly visible on December 31 in that year, which 

 is the date of the last observation at Pulkowa, and but 

 for the intervention of clouds, observations would have 

 been possible. Nevertheless neither object could have 

 been detected, in all probability, if the positions had not 

 been pretty accurately known, and thus the recovery of a 

 faint periodical comet when it first comes within reach, 

 subject as the calculated places may be to material error, 

 is a very different matter to distinguishing a faint object 

 when we know exactly where to look for it. 



Cn this, the first return, of Tempel's comet of 1873 

 since its periodicity was discovered, the date of perihelion 

 passage upon which the geocentric path depends may 

 reasonably be expected to be several days in error, 

 although not necessarily so. The following would be the 

 variations in right ascension and declination on May 18 

 and 30, caused by assuming the perihelion passage to 

 occur four days earlier or four days later than the time 

 calculated by M. Schulhof : — 



P. P. four days earlier. 

 R.A. 



Decl. 



May 18 ... -f 16-7 ... - 50 

 „ 30 ... -f 17-9 ... -45 



This comet was discovered on the night of July 3, 1873, 

 by M. Tempel, at the Observatory of Milan, in the con- 

 stellation Cetus. Its short period of revolution was 

 pointed out about the same time by M. Schulhof and Mr, 

 Hind, from the observations made in July. At aphelion 

 it approaches the orbit of Jupiter within 0-64, and in 

 about 309° heliocentric longitude is within 0-052 of the 

 orbit of Mars. 



CCCULTATION OF Mars.— On the evening of June 3 

 Mars will be occulted by the moon, and no other occulta- 

 tion of a bright planet, visible here, will take place for 

 several years, until 1882 or later. At the Royal Observa- 

 tory, Greenwich, the immersion will occur, according 

 to the tables, at loh. im. 93., and the emersion at 

 loh. 42m. 49s., mean times, the angle at emersion 

 counted as in the Nautical Almanac for inverted image 

 being 288°. 



