Feb. 8, 1877] 



NATURE 



323 



show an amount of knowleilge equivalent to that which in Clas- 

 sics or Mathematics usually gains an Exhibition or vScholarsbip 

 in the College. 



King's Colks;e. — On Wednesday, April 4, 1877, and following 

 days an Exhibition in Natural Science will be offered for com- 

 petition. The Exhibition is worth about 90/. a year, and is 

 tenable for three years, but not with any other Exhibition or 

 Scholarship of the College. 



Christ's College. — One or more in value from 30/. to 70/., 

 according to the number and merits of the candidates^ tenable 

 for three-and-a-lialf years, and for three years longer by those 

 who reside during that period at the College. 



Gonville and Cains College. —One of the value of 60/. per 

 annum. The examination bei^ins on the last Tuesday in the Lent 

 term. College examinations are held annually in the Easter 

 term for Medical and Natural Science Students who have passed 

 the University previous examination, in Anatomy, Physiology, 

 Physics, Chemistry, &c,, at which prizes and Scholarships of the 

 value of from 60I, to 20/. are awarded to members of the Col- 

 lege of the first, second, and third year, on precisely the same 

 conditions as those for other branches of learning. Exami- 

 nations are also held, as vacancies occur, in Botany and Com- 

 parative Anatomy in its most general sense (including Zootomy 

 and Comparative Physiology), for two Shuttleworth Scholar- 

 ships, each of the value of 60/. per annum, and tenable for 

 three years. The successful candidates for the Tancred Medical 

 Studentships are required to enter at this College ; these student- 

 ships are five in number, and the annual value of each is 100/. 

 Information respecting these may be obtained from B. J. L. 

 Frere, Esq., 28, Lincoln's Inn Fields, London. 



Clare College. — One of the value of 60/. per annum, tenable 

 for two years at least. The examination will be held on March 20. 

 Downing College. — One or more of the value of 60/. per 

 annum. The examination will be on or about April 9. 



.Sidney College. — -One of the value of 60/. The examination 

 will be on March 20. 



Emmanuel College. — One Foundation Scholarship of 70/., 

 tenable till the holder is of standing for the degree of B.A., and 

 four Minor Scholarships (two of 70/., and two of 50/.), tenable 

 for two years, will be awarded. The examination will take 

 place on March 20. 



Non-Collegiate Students. — An Exhibition each year is given by 

 the Clothworkers' Company, value 50/. per annum, tenable for 

 three years. Examination about Christmas, open to Non-Col- 

 legiate Students who have commenced residence in the October 

 term, and to any who have not commenced residence. Informa- 

 tion to be obtained from the Rev. R. B. .Somerset, Cambridge. 

 The subjects, it may be stated generally, are Chemistry, 

 Physics, Geology and Mineralogy, Botany, Comparative Ana- 

 tomy and Zoology, and Physiology ; but for detailed information 

 application must be made to [the tutors of the respective Col- 

 leges. 



Although several subjects for examination are in each instance 

 given, this is rather to afford the option of one or more to the 

 candidates, than to induce them to present a superficial know- 

 ledge of several. Indeed, it is expressly stated by some of the 

 Colleges that good clear knowledge of one or two subjects will 

 be more esteemed than a general knowledge of several. In 

 some instances, as at Caius College, each candidate is required 

 to furnish beforehand a list of the subjects in which he desires 

 to be examined. 



There is no restriction on the ground of religious denomina- 

 tions in the case of these or any of the Scholarships or Exhibi- 

 tions in the Colleges or in the University. 



Some of the Colleges do not restrict themselves to the number 

 of Scholarships here mentioned, but will give additional Scholar- 

 ships if candidates of superior merits present themselves ; and 

 other Colleges than those here mentioned, though they do not 

 offer Scholarships, are in the habit of rewarding deserving 

 students of Natural Science. 



It may be added that Trinity College will give a Fellowship 

 for Natural Science, once, at least, in three years, and that such 

 a Fellowship will be given in the present year. The examina- 

 tion will take place at the end of September, and will be open 

 to all Bachelors of Arts, Law, and Medicine of the University, 

 of not more than three years' standing from their first degree. 

 Application should be made to the Rev. Coutts Trotter, Tutor of 

 Trinity. Most of the Colleges are understood to be willing to 

 award Fellowships for merit in Natural Science equivalent to 

 that for which they are in the habit of giving them for Classics 

 and Mathematics, 



OUR ASTRONOMICAL COLUMN 



The Comet of 1812. — In view of the approaching return of 

 the comet discovered by Pons on July 20, 18 12, which beyond 

 doubt, at the time of its visibility, was moving in an elliptic 

 orbit with a period of about seventy years, it is not without 

 interest to inquire into the particular circumstances of its track 

 in the heavens, and distance from the earth and sun, under 

 different assumptions, with regard to the time of the next peri- 

 helion passage. The case is a very different one to that of 

 Halley's comet (which has a period only five or six years longer 

 than that of the comet in question) at its last appearance in 1835, 

 or even at the previous one in 1759. The semi-axis major of 

 Halley's comet was already known with considerable precision, 

 from this body having been observed at several returns to peri- 

 helion since the year 1456, and in 1835 an exceedingly close pre- 

 diction of the date of the comet's arrival at its least distance from 

 the sun was made, it is true, after most laborious calculation. 

 Pons' comet of 1812 is not thus situated. So far, no previous 

 appearance has been recognised, and we are, therefore, depen- 

 dent entirely upon the observations made in 1812 for the deter- 

 mination of the length of the revolution, and hence of the epoch 

 of its next return. Within what limits these observations admit 

 of the period being assigned, has not perhaps as yet been full/ 

 examined, but it appears probable they will be wider than in the 

 case of another comet of similar length of revolution, that dis- 

 covered by Olbers on March 6, 1815, the perturbations of which 

 were calculated for the present revolution by Bessel, who fixes 

 the return to February, 1887, though the prediction may be 

 materially in error. 



From the great inclination of the orbit of Pons' comet to the 

 plane of the earth's annual path, it is perhaps possible that with 

 a fairly accurate prediction of its position, it might be detected 

 with very powerful telescopes, no matter at what time of the year 

 the perihelion passage falls, but such prediction being impracti- 

 cable, it is desirable, as we have already remarked, to trace out 

 the apparent path of the comet amongst the stars, on different 

 hypotheses as to date of arrival at perihelion. At present we 

 shall confine our remarks to the more favourable conditions 

 under which it is possible for the comet to appear. 



The nearest approach of the comet's orbit to that of the earth 

 (0'i85) occurs near the passage of the descending node, about 

 9I days before the arrival at perihelion, and the longitude of the 

 descending node being in 73° 56' for 1880, we may assume the 

 perihelion passage to take place on December 150. In this 

 case the comet would have the following track : — 



If the perihelion passage be taken eight days later, when the 

 earth and comet would have about the same heliocentric longi- 

 tude, with the latter body in perihelion, we shall have : — 



Under such conditions it appears very improbable that the 

 comet could escape observation. At its discovery in 1812 it was 

 a diffused telescopic nebulosity, but to\vards the end of August 

 it became visible to the unaided eye, and about the time of 



