Fepruary 18, 1897 | 
NATURE 
S734 
OUR ASTRONOMICAL COLUMN. 
Prizes IN ASTRONOMY.—The Belgian Government has 
offered a sum of 300,000 francs, without distinction of nation- 
ality, on the occasion of the Exhibition to be held this year in 
Brussels, to the authors of the best solutions of some important 
questions selected by special Committees of the different Sections. 
The problems which more especially interest us, namely those 
on astronomy, are as follows (the values of the Ist, 2nd, and 
3rd prizes being 900, 600, and 500 francs respectively). 
A. Construct an apparatus by which relative measures of the 
value of g on board ship may be made. 
B. Construct an apparatus to show the effects similar to those 
of the germination of the canals on Mars, and which may explain 
the actual observed phenomena. 
D. Invent a means by which planetary details may be photo- 
graphed as clearly as they can be observed. 
E. Find a method by which the sun can be observed at any 
time as if it were totally eclipsed. 
F. Indicate a sure method of determining the amount and 
direction of movement of the solar system. 
Prizes of 300 and 200 francs are offered for the authors of the 
best answers to the following :— 
A. Investigate, from the point of view of computation of 
astronomical observations, whether the formule of Laplace, 
relative to the movement of rotation of the earth, are or are not 
more exact than those of Oppolzer. 
B. Improve in some way the measures made with the 
meridian circle (elimination or determination of personal error, 
instrumental corrections, &c.). 
C. Write a critical essay on the fundamental principles of 
mechanics, and differentiate between what is purely rational and 
what is in the domain of experience. 
D. Improve in some point the actual state of our knowledge 
of cosmogony. 
E. Improve our knowledge of gravity, either by a new dis- 
cussion of old observations or by new methods. 
F. Improve the magnetic chart of any country, either by a 
fresh discussion of old observations or by the use of new ones. 
G. The theory of the motion of rotation of the terrestrial pole. 
H. Give complete theoretical formule for the variation of | 
latitudes, and determine by them the periods theoretically. 
I. Investigate whether a new term for the secular acceleration 
of the moon can exist. 
DovusBLe STaR MEASuRES.—Vol. x. Part 1 of the publica- | 
tions of the Washburn Observatory contains the observations of 
double stars, made with the 4o cm. Clark equatorial telescope of | 
this observatory between the years 1892 and 1896. The stars 
selected were for the most part well-known binary systems in 
rapid motion; but additions have at times been made, among 
which were eleven stars of very slow relative motion included 
in the list of cireumpolar stars selected by Otto Struve for 
observation as comparison stars. Only nights on which the 
“*seeing”’ was sufficiently good for the employment of high 
magnifying powers were used. The director, Mr. George Com- 
stock, states, with regard to the possible error due to the position 
of the observer's head: ‘‘I have uniformly held my head in 
such a position during the observations that the line joining the 
eyes was either parallel or perpendicular to the line joining the 
star images.” The measurements of distance were made by 
placing the micrometer threads upon the discs of the stars. In 
the cases of very close and difficult stars, another method was 
adopted, applied only when the distances were below 05. A 
discussion of the probable errors shows that for distances less 
than 0”60, a single estimate of distance may be assumed con- 
stant and equal to + o”o40. The coordinates of the stars in 
the list are referred to the equinox of 1880'0. 
LuNAR PHOTOGRAPHS.—The February number of the Bu/- 
detin de la Soctété Astronomigue de France contains an interest- 
ing article, by M. Camille Flammarion, on lunar photography. 
The reader will find there some excellent reproductions of the 
Paris negatives, the latter equalling, if not surpassing, any 
photographs obtained. A magnificent phototype, from a photo- 
graph taken February 14, 1894, shows the moon nine days from 
the lunation, Copernicus standing out magnificently clear on the 
terminator. All the details are wonderfully sharp, and the con- 
trast leaves little to be desired. M. Loewy is to be congratulated 
on the high state of efficiency which he has attained in his 
photographic investigations of the lunar surface. 
NO. 1425, VOL. 55 | 
REPORT ON THE CORAL REEF AT 
FUNAFUTI! 
Prefatory Note by Prof. T. G. Bonney, F.R.S., Vuce- 
Chairman of the Committee. 
N presenting, as desired by the Committee, Prof. Sollas’s 
report on the attempts to ascertain, by boring, the structure 
of the atoll of Funafuti and on other investigations simul- 
taneously undertaken, I avail myself of the opportunity of 
expressing the gratitude which is felt by its members to our friends 
in New South Wales, who have given such real and substantial 
help, especially by the loan of machinery and skilled workmen, 
in putting the project into execution ; and among them chiefly 
to Prof. Anderson Stuart (who has been practically another 
Secretary in Australia), Prof. Edgeworth David, Mr. W. H. J. 
Slee (Chief Inspector of Mines), and Sir Saul Samuel (the 
Agent-General of the Colony in England). I shall venture also 
to acknowledge gratefully the services of Captain Field and the 
officers of H.M.S. Penguzn, and the unstinted labour which has 
been given by Mr. W. W. Watts, our Secretary in London, in 
carrying out our plans. In conclusion, may I express, speaking 
for myself, my earnest hope that another attempt will be made 
to determine the true structure of an atoll. I think, however. 
that our experience on this occasion shows that the attempt can 
be much more easily made, and with a far greater probability of 
success, if Australia instead of England be the base of opera- 
tions, and I trust that before long the colony of Sydney will 
initiate an expedition, and we shall co-operate with them as 
cordially as they have done with us. 
Report of Prof. Sollas, F.R.S. 
H.M.S. Penguin having come to anchor in the lagoon of 
Funafuti on the afternoon of Thursday, May 21, Captain Field 
at once landed with Lieut. Dawson, Ayles (the foreman of the 
boring party), and myself, and we proceeded to make arrange- 
ments for our work on the island. A site for boring was 
chosen near the sandy beach of the lagoon, conveniently 
situated for the landing of gear, less than half a mile to the 
south and west of the village of Funafuti, and near the village 
well, which supplies a small amount of brackish but drinkable 
water. The work of landing was commenced the next morn- 
ing, and completed by May 26. The erection of the boring 
apparatus was at once taken in hand, and on June 2, twelve 
| days after our arrival on the island, all was in readiness for 
s 
commencing operations. On June 3 the 6-inch tubes were 
driven into the sand, and by June 6 they had been advanced 30 
feet ; the 5-inch pipes were then entered, and everything made 
ready for inserting the diamond crown and commencing to drill 
on Monday, June 8. On June Io it was arranged that the 
work should proceed by shifts, so that the drilling might be 
carried on continuously day and night. During the first shift 
the crown had been advanced 20 feet, making the total depth 
then attained 52 feet 9 inches ; during this shift, fragments of 
highly cavernous coral rock were brought up in the core barrel 
from a depth of between 40 and 50 feet. 
On June 11, a depth of 85 feet having been reached, it was 
found necessary to ream the hole preparatory to lining, and by 
June 15 the necessary reaming and lining had been completed. 
Up to this, although we had been somewhat disappointed at 
our slow rate of progress, occasioned partly by the unfavourable 
nature of the ground and partly by the frequent failure of our 
machinery, we had anticipated nothing worse than the possi- 
bility of finding our allotted time exhausted before we had 
reached a depth of 1000 feet; but now, on setting the crown 
to work, it very soon ceased to advance, and Ayles shortly 
afterwards came to me to announce that, in his opinion, the 
boring was a failure. Nevertheless, some further progress was 
subsequently made, and on Tuesday, June 16, a depth of 105 
feet was attained. It then became once more necessary to 
ream and line the hole. Attempts to ream were continued all 
through Wednesday and Thursday, but without success ; sand 
poured into the hole, and the reamer could not be driven 
through it. Efforts were made to remove the sand by a sand- 
pump, but proved unavailng, the sand flowing in faster than it 
could be pumped out. Ayles assured me that it was impossible 
to descend another foot, and that he considered further labour 
as time and money thrown away. We decided therefore to 
1 “* Report to the Committee of the Royal Society appointed to Investigate 
the Structure of a Coral Reef by Boring.” By Dr. W. J. Sollas, F.R.S., 
Professor of Geology in the University of Dublin. Received December 
1895. Read, February 11, 1897. 
