Jan. 14, 1875] 



NATURE 



203 



2h. om. 6s. local time. 

 4m. 6s. 



6r 



Totality begins at Mergui at . 

 Duration 

 Sun's altitude 



Totality begins at Tenasserim at 2h. 2m. 7s. local time. 

 Duration ... ... ... 3m. 57s. 



Sun's altitude 60° 



Neatly midway between the above places, or where a 

 " Conical Peak " is marked on the Admiralty Chart, the 

 total eclipse, continues 4m. 14s. 



" ISangkok (Sinm) will be found to lie rather north of 

 the central line. The circumstances of the eclipse at this 

 point arc as follows (long. 6h. 42m. 6s. E. ; lat 13° 42*5" N.) 



" The partial eclipse begins at oh. 51m. 6s. mean time 

 at Bangkok, 134° from the north point towards the west, 

 and i6S° from the vertex eastward, for itircci image ; the 

 sun at an altitude of 76'-\ The total eclipse begins at 

 2h. 13m. 7s. and continues 3ni. 54s., the sun about 57° 

 high, and the partial phase ends at 3h. 33m. 



" The invitation extended to British and other astro 

 nomers by the King of Siam, to observe this interesting 

 and important phenomenon within his dominions, maybe 

 expected to bring together a number of competent ob- 

 servers in the vicinity of Bangkok ; and in selecting 

 localities for astronomical stations, it must be very 

 desirable to be enabled to form some idea of the extent 

 of error to which the predicted track of the central line 

 may be subject. On this account I have made a further 

 direct calculation for the Siamese capital, taking the 

 moon's position from the American Ephemeris,' in which 

 the Tables of Prof. Peirce are employed. With elements 

 thus modified, the partial phase is found to commence at 

 oh. 50m, 42s., or 24 seconds only earlier than by Hansen's 

 Tables ; totality begins at 2h. 13m. 32s., and continues 

 3m. 59s. Generally I may remark that between the 

 longitudes of the Nicobars and Siam, the track of central 

 line by the American Tables has about five minutes 

 greater latitude than that given by Hansen's Tables. 



" (For any point in Siam in the neighbourhood of Bang- 

 kok, the Greenwicli time of commencement of the partial 

 eclipse will be given closely by the following formula : — 



Cos. 'M = -0-08471 -[012053] sin. I + [0.12430] ros. I, cos (L-'i-ji'^ io"i) 

 i = i8h. 55m. 585. -[3-71146] sin. TO + [3-83098] sin. / 



-[3 83692] COS. /, COS. (i-4° 14--5) 



The Greenwich mean time of beginning and ending of 

 totality may be found from 



CosOT= -17-5228- [1-74616] sin. /+ [1-68499] COS. '. COS. (£-150° 25-5) 

 t = l8h. i7in. 58-5S. ^ [2-09477] sin. w + [3-77348] sin. / 



- [3-84594] COS. /, COS. (L + 16° 32-8). 



"In the above formulae L expresses the east longitude of 

 the point from Greenwich, taken positive ; / is its geo- 

 centric latitude, and the quantities within the square 

 brackets are logarithms. Upper sign for beginning of 

 totality, lower sign for ending.) 



" It has been stated above that the eclipse of next April 

 may probably be the most favourable for observation 

 that can take place during the present century. In the 

 eclipse of 1S7S, July 29, the duration of totality is shorter, 

 and the same is the case in the echpscs of 18S2, 1S87, 

 1900, &c. In the eclipse of 1886, August 29, the only 

 easily accessible and favourable station appears to be the 

 Island of Grenada, in the West Indies, where the dura- 

 tion of total eclipse is 3m. 15s., commencing at 7h. lom. 

 A M. local time, with the sun at an altitude of 20° ; thence 

 the course of the central line is over the North and South 

 Atlantic Oceans, to a point on the African coast north of 

 St. Philip de Benguela. In the eclipse of 1892, April 26, 

 the central line appears to have a sea-track through nearly 

 its whole extent, if indeed it touches land at any point, 

 which requires a more precise computation than I have 

 yet made to determine. The eclipse of 1893, April 16, is 

 the only one that can compare favourably, as regards length 



of totality and track, with that of the present year : at a 

 point in the vicinity of Ceara, in the Brazils, the duration 

 of total eclipse is 4m. 44s. with the sun at an altitude of 

 76°." 



We may conclude our article by stating that the obser- 

 vations for which the Council of the Royal Society have 

 obtained a promise of a grant in aid amounting to i,coo/. 

 will be limited to photographing the spectra of the chromo- 

 sphere and coronal atmosphere. 



For this purpose a sidcrostat has been placed at the 

 disposal of the Royal Society, and another will be ready 

 ill time. These instruments have been made by Messrs. 

 Cooke and Sons, of York, who have in some respects, with 

 their usual skill, improved upon Foucault's model. As an 

 instance of international courtesy which must not be un- 

 recorded, we may state that M. Leverrier would have 

 placed the original instrument devised by Foucault 

 himself, and now at the Paris Observatory, at the dis- 

 posal of the Royal Society, had it not been constructed 

 solely for the latitude of Paris. 



Besides siderostats, it is proposed that equatoreals shall 

 be sent out also, provided with apparatus for spectrum 

 photography, quartz prisms and lenses being generally 

 employed. 



The Secretary of State for India (Lord Salisbury), the 

 Viceroy of India, and the Admiralty officials are all hearty 

 in their co-operation. It is hoped that Col. Tennant and 

 a strong staff of assistants will also be on the scene of 

 action. 



Although the time is short, then, we may fairly hope 

 that good work will be done. Of this we may be assured, 

 that whether the observers be many or few, whether the 

 weather be good or bad — and General Strachey considers 

 the chances all that can be wished for — the action of the 

 Royal Society and of the Government will redound to 

 the credit of English science, and a bright page may 

 be added to the scientific annals of our time. 



Editor 



COUNT RUM FORD'S COMPLETE WORKS 



The Complete. Works of Count Rumford. (Published by 

 the American Academy of Arts and Sciences.) 



THE American Academy of Arts and Sciences is 

 doing good service and teaching the Old World a 

 sound practical lesson by undertaking the pubhcation of 

 such a work as this. The question of what form should 

 be given to the monument of a great man is often dis- 

 cussed, and fairly admits of much debating ; but when 

 the benefactor of humanity whose memory is to be pre- 

 served is one who has done the high service of extending 

 the boundaries of science, we may safely venture to affirm 

 that whatever other monuments may be erected, the first 

 should be a complete and carefully compiled record of all 

 his researches. The demand for this arises from the 

 manner in which the results of original scientific work 

 are usually communicated to the world, i.e. in the form of 

 papers read before learned societies or contributed to 

 magazines, or published as pamphlets, and thus scattered 

 far and wide and liable to be forgotten or even altogether 

 lost. Such a publication should precede all other forms 



