OOCULTATloX. 



OCCUPANCY. 



.of stars by the moon; such of which as cut be made useful in 

 Aw Uw longHode are given yearly in he Nautical Almanac. 



lltL moon were (like the star) .u distant that two spectators at 

 tmrly opposite poiats ol the earth would not be sensibly removed from 

 each other in space when thrir distance from each other was compared 

 with their common distance from the moon, then all observers, where- 

 soever ritTnfrr 1 . would see the moon begin to hide a star at the same 

 instant. Thar would all then be able to note by their different clocks 

 the absolute instant of the same phenomenon ; and [Loxum < 



of dock-time at this absolute instant would give their 



- 



of longitude. But the proximity of the moon makes it 

 that one nlariini (at A) may we no ooeulutioo at the time 

 when eooh a phenomenon hu occurred to another (at B); and makes it 



the bruiht ringi which surround the image of a itar as seen in a | 

 telewope. It is plain also, for the same reason, that the aggregai 

 light produced by the aggregate of nil the luminous j,,.mts ..t the 

 moon's disc, is not a lummous image bounded by a sharp outline, at 

 what we consider the geometries! outline of the imago, but that th* 

 geometrical outline is fringed by a band f illumination, prodooed by 

 the interlacing and superposition of all the systems of ring*. 1 1 < 

 follow* that when, with a very fine telescope we see the moon's limb 

 very sharply defined, and apparently surrounded by immediate 

 darkness we do in reality see it erroneously. Mr. Airy conceives that 



certain that two observers cannot see the beginning of an oecnlt.it ion 

 at the name instant of absolute time. Both therefore must deduce 

 from their own observed times of commencement, and from their 

 knowledge of the moon's place and motions, the times, at their several 

 places, at which a spectator situated at the earth's centre would see the 

 Mar touch the moon's limb ; and this being done, they are in the same 

 position as if the moon had been too distant to require such a process. 

 If, in this work, we had given the details of astronomical calculations, 

 we should not have separated that required in reducing an occultation 

 to the earth's centre from the similar case which occurs in an eclipse 

 of the sun or a transit of Venus : the principles employed in all arc 

 identical, though the first process is rendered more simple than the 

 second or third, by the very great distance of the star, which may be 

 considered as marking the same point of the heavens at all places. For 

 the value of observed occultations in finding the longitude, see the 

 article LOXGITCDE. 



Here we might close this article, if it were not for a singular cir- 

 cumstance which sometimes occurs ; and which cannot be traced either 

 to the character of the telescope employed, of the observer, of the 

 weather during the observation, or of the particular star under occulta- 

 tioo. When the moon approaches the star, instead of an instant of 

 contact, followed by disappearance of the star, the 

 latter for a few seconds is frequently thrown upon the 

 moon, as if it were the nearer body, and were going to 

 cross the moon's surface, as Venus does that of the sun 

 during a transit. While this is taking place, which 

 sometimes lasts until the star has fairly left the moon's 

 limb or border, the star preserves its light, though it 

 frequently undergoes a change of colour. Aldebaran, 

 whose natural colour is inclining to red, has been seen to present this 

 phenomenon much more frequently than any other star : but 9 Tauri, 0' 

 and f Pleisdum.Spica Virginia, Kcgulus, 7 Libra, 132 Tauri, a 1 Cancri, 

 49 Libre, A Aquarii, 249 Aquarii, 187 Sagittarii, 7 Tauri, p Leonis, p 

 Oeminorum, t Cancri, t Piscium, Ac., have been seen more or less to 

 come upon the moon's limb. See a detailed list of quotations from 

 the different observers in a paper by Mr. South, On the Occultation 

 of I IHncium by the Moon,' in the third volume of the ' Memoirs ol 

 the Astronomical Society.' It is to be noted that many of these 

 1 jiy..>n^. did not exhibit the whole of the phenomenon, but made 

 toe star hang for some seconds upon the moon's limb, instead ol 



approaching again in the years 1829 



immediately disapp 

 The occupations of 



ung agaii 



and 1830, the Society just mentioned invited the particular attention 

 of astiimiminis to them. The consequence was, a large number <>: 

 communications from different part* of Europe, which are printed in 

 the fourth volume of their Memoirs. Nothing can be more different 

 than the results : some, now saw the phenomenon for the first time 

 others, who had seen it before, did not see it ; some, who had never 

 Men it before, continued unable to do so. Of six observers at the 

 Boyal Observatory, five distinctly saw the projection on the moon'i 

 limb, and one saw it hang on the edge of the moon five or six seconds 

 before it disappeared. Of three at the Observatory of Paris, two 

 distinctly saw the projection, and one saw the star disappear install 

 taneoiuly , leaving a shade ("ombre ") on the part of the moon at whicl 

 H disappeared. The majority saw the star either projected or hanging 

 on the moon's edge. It is to be noted that this phenomenon has beei 

 seen at the dark edge of the moon as well as at the enlightened. It 

 cause is matter of much diversity of opinion. 



The most recent explanation is due to Mr. Airy, who in the year 

 1859 communicated a paper on the subject to the Royal Astronomies 

 Society, which is to be found in the twenty-eighth volume of th 

 Memoirs 'published by that body. Mr. Airy remarks, " that on th 

 principles of the undulatory theory of light, the image in a telesoop 

 of any luminous point, whether a star or a portion of the moon 

 illuminated surface, is not a point." This is exemplified in the case o 



light beymd that curve ; but that in the excitement and int. nli 

 observing an occultation, the state of the sensational organisation i 

 probably much changed, and as the presumed time of the phenol 

 comes nearer and nearer, the eyo probably becomes more and ' 

 m-nsiblc to the faint diffused light, and the visible 1 

 extends further and further into the darkness. In numer. u 

 when the boundary of the moon's light has swelled till it < 

 star, it swells no further, and the star hangs on the moon's limb. 

 According to Mr. Airy, it seems perfectly conceivable, that the mental 

 contemplation of the relation of the positions of the moon and star 

 hich is implied in the phenomenon that is to be observe.'., 

 requcntly so far act on the sensibilities, that when that relation 

 n:miely, contact) U once gained, the mental effort does not make the 

 lense more acute than is necessary, and may even somewhat relax as 

 lie denser light of the moon reaches the star. This explanation, it 

 ill be seen, refers the phenomenon to the principle of the irradiation 



OCCUPANCY. This term in English law Dignifies the taking 

 XMsession by any person of any thing which has no owner (Br. 

 ol. 8, 6), and the general doctrine, as stated in Bracton, is derived 

 rom the Jo* Ucntitim of the Itoinan lawyers, as explained in the 

 Digest' (lib. 41, tit 1, s. 1, 3, 5, &c.). That use of the term which 

 vill be here explained has reference to the occupation of land. 



An estate fur outer rie, or for the life of another person or persons, 

 lad formerly some peculiar qualities incident to it. If a man h 

 state in land for his own life, such estate was of course determined by 

 lis death. But if he had an estate in land for the life of another 

 >erson, and he or liis assignee died before such person, tin 

 lot determined, and yet there was nobody to take it, inasmuch as it 

 ould not go to the heir, nor, being a freehold interest, to the es> 

 or administrator. Such an estate belonged to the first person who 

 could take possession of it, and he was entitled to hold it as general 

 occupant till the expiration of the life for which it was originally 

 granted. But if the original grant were to A and his heirs, for th. 

 of B, and A died during the life of B, the heir of A took the estate as 

 special occupant that is, as a person designated in the original grant. 

 Sometimes the heir was said to take the estate as a descendible free- 

 Hold, though the estate is admitted not to be an estate of inheiv 

 and therefore not subject to courtesy or dower, it not bcin 

 that to say an estate is not an estate of inheritance and yet is descend- 

 ible, is a contradiction, for descent implies an heir who takes a 

 Still it appears from Bracton (fol. 26 4, 62 b), that if lands were .given 

 to a man and his heirs for the life of another person, the heir could 

 recover the land by an assise of mart (Canccttor, because the ancestor 

 died seised as of fee, and a man could claim by an assise of 

 <faneetor any land of which his ancestor was seised as of a fee 

 ftodo); and hence it has been concluded that the. heir took n 

 special occupant, but that he took a descendible freehold. This subject 

 of occupancy, general and special, is discussed at great length and with 

 considerable acute-ness by Vaughon, Justice. (Vaughan, II olden i 1 . 

 Sinallbrooke.) 



In the case of copyhold, when there was no special occupant, the 

 lord took the estate; for the lord, having the freehold, was also con- 

 to have the possession ; and therefore " vacancy," tl: 

 condition to any other person's title by occupation, was wanting. In 

 the case of a rent or other incorporeal hereditament, when tin i 

 no special occupant, inasmuch as there could be no entry, there could 

 of course be no possession or title by general occupancy. 



It is stated by Bracton, that if land win given to a man for the life 

 of another without any mention of his heirs, the land on the death of 

 the donee did not immediately revert to the donor, unless the donee 

 died intestate, or unless, though he made a will, he had made no 

 mention of his interest in. the land as of a term of years, but that if 

 he had disposed of it in his will as of a chattel, such disposition was 

 valid. (Bracton, fol. 27 a; see Doe dem. Blake, 6 T. li., 291.) This 

 power of disposing of a freehold interest in land must have fallen into 

 disuse after the time of Bracton ; for it U quite inconsistent with the 

 doctrine of general occupancy as stated by Littleton, and also with the 

 general rule of law, which prevented freehold interests in land from 

 being disposed of by will, before the Statutes of Wills passed in the 

 reign of Henry VII I. But the Statutes of Wills were limited to 

 estates in fee simple, and no power to devise estates./ 

 existed at law before it was given by the Statute of Frauds. 



Since the passing of the Statute of Frauds (29 Cor. II. c. 3), general 

 occupancy (with, perhaps, one exception, hereafter mentioned) has 



