The great comet of 1882 was watched right up to the Sun’s limb by Messrs. Finlay and Elkin at the Cape of Good Hope on Sept. 16, 1882. The comet was actually seen to disappear at the margin, and not a vestige of it could be traced during its transit across the solar disk. The nucleus of the comet was 4” in diameter, and before transit it looked as bright as a part of the Sun’s surface; but it was quite invisible when projected on the disk. The alleged observations by Pastorff and Stark, which were construed into visible transits of comets, are therefore thoroughly disproved, and will require another interpretation.
At the time of the total solar eclipse of May 17, 1882, a bright comet was observed near the Sun. It was a striking object visible to the naked eye. In the photographs which were taken of the eclipse the comet is well shown, but this body escaped subsequent observation, so that its orbit could not be determined.
Naked-eye Comets.—Arago mentions that twelve comets were visible to the naked eye during the period from 1800 to 1853, but there appear to have been certainly thirty comets fulfilling this condition, and I believe a careful search amongst cometary records would further augment the number. During the ten years from 1880 to 1889 inclusive there were no less than sixteen comets perceptible to unaided vision, and a considerable proportion of these were fine comets. It is very rarely that two naked-eye comets are to be seen at the same epoch, as in August 1881 and at the end of April 1886.
Comet-seeking.—For a long time after the invention of the telescope comet-seeking does not appear to have been undertaken in a methodical way, and to have formed the habitual work of certain observers. But the expected return of Halley’s Comet in 1759 roused observers to take the initiative in a branch of practical research which in after years was destined to prove remarkably productive. Messier, Palitzch, and others began a system of sweeping the heavens for the predicted comet; and it had a successful issue, for Palitzch, who did not relax his labours even on Christmas day, alighted upon the coveted prize on Dec. 25, 1758. Since that time a regular search after comets has been maintained. Messier pursued it with indomitable energy through a long period of years, and achieved many successes. It is said of him that on one occasion he was anticipated in a discovery by Montaigne, and he appears to have deplored the loss of the comet more than the loss of his wife, who was lying dead at the time. A friend visited him, and spoke a few words of sympathy in reference to his bereavement, but Messier, in despair about the comet, exclaimed: “I had discovered twelve—alas! that I should be robbed of the thirteenth by Montaigne!” and his eyes filled with tears. Recollecting himself, and appreciating the loss he had sustained in his wife, he added, “Ah, this poor woman!” Messier encountered some serious obstacles to his favourite pursuit. Breen, in his ‘Planetary Worlds,’ mentions that Messier, while walking in President Saron’s garden, fell into an ice-house, and was disabled for a time. Later on “the revolution deprived him of his little income and every evening he was wont to repair to the house of Lalande to replenish the supply of oil for his midnight lamp. The political storm necessitated his removal to another neighbourhood, where he no longer heard the clocks of forty-two churches sounding the hours during his night-watchings.” Messier discovered all his comets with a small 2-foot telescope of 2½ inches aperture magnifying 5 times and with a field of 4°.
Dr. Olbers, of Bremen, was another diligent student in this field. He did not effect many discoveries, but, from an upper apartment of his house, he observed nearly all the comets which appeared during half a century.
During the first twenty-seven years of the present century, Pons discovered the majority of the comets that were seen. He was a door-keeper at the Observatory at Marseilles, and owing to the teaching and encouragement he received from Thulis, the director, he achieved phenomenal success as a comet-hunter.
Discoveries of comets have rarely been effected in England. This is chiefly to be assigned to two circumstances. First, because the labour involved in seeking for these bodies has never perhaps been pursued to an equal degree and with the same tenacity as it formerly was in France, and as it has recently been in the United States; and second, because the cloud-laden skies of England oppose the successful prosecution of a research in which a clear atmosphere is eminently desirable.
Though comet-seeking does not always produce new discoveries, it is certainly entertaining to those engaged in it; for one of the most agreeable diversions of telescopic work is to scan the firmament with a large-field comet-eyepiece, which exhibits the most pleasing views of star-groups, coloured stars, nebulæ, and telescopic meteors.
The operation of sweeping for comets is attractive from other aspects, though it undoubtedly needs close application, patience, and much caution. The possibility of seeing a comet in the field at any time proves a constant source of allurement to the observer, and sustains his enthusiasm. The glimpsing of a nebulous object, and the expectation (before it has been identified) that it may prove a comet, induces a little excitement which pleasantly relieves the monotony that might otherwise be attached to a sedulous research of this nature; and it is one in which amateurs may suitably engage with a fair prospect of success. Instruments of great power, refinement, and expense are not required. It is rather a work calling for the exercise of patience and acute perception, and for that tireless servitude which those only who have an inborn love for it can maintain.
English Weather and Comet-seeking.—Only two new comets having been discovered in England during the last forty years some people regard our climate as in a great measure responsible for this. But the opinion seems to be erroneous. The lack of discoveries has arisen from want of effort as much as from want of opportunity. The best weather for comet-seeking is when the atmosphere is very transparent, and the stars are lucid and sparkling. Haze, fog, or cloud of any kind offers a serious hindrance. A thoroughly good night for planetary work is not usually good for cometary observation, because sharp definition is not so requisite as a very clear sky. A little fog or thin cloud, which will often improve planetary images, utterly obliterates a small telescopic comet. The air is sometimes very pure and dark after storms, and the stars remarkably bright; it is then that the best opportunities are afforded for comet-hunting. Any systematic and regular work like this may be pursued in this country with every prospect of success by an observer who will persevere in it. From some statistics printed in the ‘Science Observer,’ Boston, it appears that during the seven months from May to November, 1882, Lewis Swift was comet-seeking during 300 hours. I have no English results of the same kind, but my meteoric observations will supply a means of comparison. From June to November, 1887 (six months), I was observing during 217 hours, and for a nearly similar period during the last half of 1877, though in each year work was only attempted with the Moon absent. My result for 1887 averages 36 hours per month, which is little less than the average derived from the comet-seeking records above quoted. It is therefore fair to suppose that as much may be done here as in some regions of the United States. Mr. W. R. Brooks wrote me in 1889, saying: “We have much cloudy weather in this part of America. While in other portions of the country clear weather abounds, it is not so in this section, where much of my work has been done. This is a most fertile section—the beautiful lake region of N.Y.,—but it is for this reason a cloudy belt. It is far different in Colorado and California. In the latter place, at the Lick Observatory, I hear they have 300 clear nights in the year—a paradise for the astronomical observer! My former site, the Red House Observatory, Phelps, N.Y., is only six miles from Geneva, and hence in the same cloudy region.” Prof. Swift also referred to the subject of weather in a letter to me dated July 30, 1889, where he says: “I arrived home, after a five weeks’ visit to the Lick Observatory, on March 1, and have not had half a dozen first-class nights since—not in thirty years have I seen such prolonged rainy and cloudy weather.” Now Mr. Brooks has discovered 13 comets in 7 years, Prof. Swift has found 8 comets (1862-1890), and in addition to these has detected more than 700 new nebulæ, all of the latter since 1883. From this it appears conclusively that if such extensive and valuable results can be obtained, notwithstanding frequently bad weather, then English observers may prove equally successful, the important factor being that similar energy and ability direct their labours.