SS i 
Sept. 24, 1885 | 
comparisons of the instrument proposed by the Committee with 
an ordinary actinometer, to find whether the arrangement 
suggested by the Committee is likely to succeed in practice. 
The Committee would therefore confine their action for the 
present to the carrying out of such a series of comparisons. 
(3) The size of the instrument might be the same as that 
of Prof. Stewart’s actinometer. (4) The instrument should 
have a thick metallic enclosure, as in the actinometer 
above-mentioned, and in this enclosure there should be in- 
serted a thermometer to record its temperature. Great pains 
should therefore be taken to construct this enclosure so 
that its temperature shall be the same throughout. (5) The 
interior thermometer should be so constructed as to be readily 
susceptible of solar influences. It is proposed to make it of 
green glass (a good absorber), and to give it a flattened surface 
in the direction perpendicular to the light from the hole. (6) 
It seems desirable to concentrate the sun’s light by means of a 
lens upon the interior thermometer, as in the ordinary instru- 
ment. For if there were no lens the hole would require to be 
large, and it would be more difficult to prevent the heat from 
the sky around the sun from interfering with the determination. 
Again, with a lens there would be great facility in adjusting the 
amount of heat to be received by employing a set of diaphragms. 
There are thus considerable advantages in a lens, and there does 
not appear to be any objection to its use. 
Third Report of the Committee, consisting of Profs. G. H. 
Darwin and F. C. Adams, for the Harmonic Analysis of Tidal 
Observations, Drawn up by Prof. G. H. Darwin.—** Record 
of Work during the past Year.” The edition of the computa- 
tion forms referred to in the second report is now completed, 
and copies are on sale with the Cambridge Scientific Instrument 
Company, St. Tibbs’ Row, Cambridge, at the price of 25. 6d. 
each. Some copies of the first report, in which the theory and 
use of these forms are explained, are also on sale at the same 
price. A few copies of the computation forms have been sent 
to the librarians of some of the principal scientific academies of 
Europe and America. In South Africa, Mr. Gill, at the Cape, 
and Mr. Neison, at Natal, are now engaged in reducing observa- 
tions with forms supplied from this edition. A memorial has 
been addressed to the Government of the Dominion of Canada, 
urging the desirability of systematic tidal observation, and the 
publication of tide-tables for the Canadian coasts. There seems 
to be good hope that a number of tide-gauges will shortly be set 
up on the Atlantic and Pacific coasts, and in the Gulf of the St. 
Lawrence. The observations will probably be reduced accord- 
ing to the methods of the British Association, and the predic- 
tions made with the instrument of the Indian Government. 
Major Baird has completed the reduction of all the tidal results 
obtained at the Indian stations to the standard forms proposed 
in the Report of 1883, and Mr. Roberts has similarly reduced a 
few results read before the Association by Sir William Thomson 
and Capt. Evans in 1878. Allthese are now being published in 
the Froceedings of the Royal Society, ina paper by Major Baird 
and myself. A large number of tidal results have been obtained 
by the United States Coast Survey, and reduced under the 
superintendence of Prof. Ferrel. Although the method pursued 
by him has been slightly different from that of the British | 
Association, it appears that the American results should be 
comparable with those at the Indian and European ports. 
Prof. Ferrel has given an assurance that this is the case; never- 
theless, there appears to be strong internal evidence that, at 
some of the ports, some of the phases should be altered by 180°. 
The doubt thus raised will probably be removed, and the paper 
before the Royal Society will afford a table of reference for all 
—or nearly all—the results of the harmonic method up to the 
date of its publication. The manual of the tidal observation 
promised by Major Baird is now completed, and will be pub- 
lished shortly. This work will explain fully all the practical 
difficulties likely to be encountered in the choice of a station for 
a tide-gauge, and in the erection and working of the instrument. 
Major Baird’s great experience in India, and the success with 
which the operations of which he has had charge have been 
carried out, render his advice of great value for the prosecution 
of tidal observation in other countries. The work also explaius 
the method of measuring the tide diagrams, entering the figures 
in the computation forms, and the subsequent numerical opera- 
tions, 
Second Report of the Committe, consisting of Prof. Balfour 
Stewart (Secretary), Mr. F. Knox Laughton, Mr. G. $. Symons, 
NATURE 
593 
Mr. R. 7, Scott, and Mr. Fohnstone Stoney, appointed for the 
purpose of cooperating with Mr. E. F. Lowe in his project of 
establishing a Meteorological Observatory near Chepstow on a 
permanent and scientific basis.—Since their re-appointment in 
1885 this Committee have met twice, and have placed them- 
selves in correspondence with Mr. Lowe, to whom the following 
letter was written by their Secretary : ‘‘ The Committee request 
me to point out to you that the main feature of your proposal, 
which interests the British Association and the scientific public 
generally, is the prospect which it holds out of the establishment 
of a Permanent institution, by means of which meteorological 
constants could be determined, and any secular change which 
may take place therein in the course of a long period of years be 
ascertained. It will be for you and the local authorities to 
_decide what amount of work of /ocal interest should be con- 
templated, and on this will the scale of the observatory mainly 
depend. The Committee are therefore unable to say what 
amount of capital would be required. They would point out 
four conditions which they hold to be indispensable :—(1) The 
area of ground appropriated should be sufficient to ensure 
freedom from the effects of subsequent building in the neighbour- 
hood. (2) A sufficient endowment fund of at least 1507. annually 
should be created. (3) The control should be in the hands of a 
body which is in itself permanent as far as can be foreseen. (4) 
The land for the site shall be handed over absolutely to the aboye- 
mentioned governing body. Until the precise amount of the 
local meteorological requirements is ascertained and further 
progress is made in the scheme the Committee consider that they 
would not be justified in any more prominent action than that 
which they have already taken. 
Report of the Committee, consisting of Profs. A. Fohnson 
(Secretary), #. G. MacGregor, #. B. Cherriman, H. T. Bovey, 
and Mr. C. Carpmael, appointed for the purpose of promoting 
Tidal Observations in Canada.—Yhe Committee, in order to 
strengthen their representation to the Canadian Government on 
the necessity of establishing stations for continuous tidal ob- 
servations, deemed it well to get the opinions of Boards of 
Trade and ship-owners and ship-masters. On inquiry it ap- 
peared that the Montreal Board of Trade were at the very time 
considering the question, which had been brought independently 
before them. On learning the object of the Committee they 
gave it their most hearty support, and addressed a strong 
memorial on the subject to the Dominion Government. The 
Boards of Trade of the other chief ports of the Dominion also 
sent similar memorials. The ship-owners and masters of ships, 
to whom application was made, were practically unanimous in 
their testimony as to the pressing need for knowledge on the 
subject. The representations were made through the Minister 
of Marine, with whom an interview was obtained, at which a 
memorial was submitted. Copies of the answers of the ship- 
masters (a large number of which had been received) were sub- 
mitted at the same time. The reply of the Minister of Marine 
stated that, owing to the large outlay on the Georgian Bay 
Survey and on the expedition to Hudson’s Bay during the past 
summer (1885), the Government did not propose to take action 
in the matter of tidal observations at present. The Committee 
have reason to believe that if the financial prospects improve by 
next session of Parliament the Government will take the matter 
into earnest consideration ; they therefore suggest that the Com- 
mittee be reappointed. 
Seventeenth Report of the Committee, consisting of Profs. Everet 
and Sir W. Thomson, Mr. G. F. Symons, Sir A. C. Ramsay, 
Dr. A, Getkie, Mr. F. Glaisher, Mr. Pengelly, Prof. Edward 
Hull. Prof. Prestwich, Dr. C. Le Neve Foster, Prof. A. S. 
Herschel, Prof. G. A. Lebour, Mr. Galloway, Mr. Foseph 
Dickinson, Mr. G. F. Deacon, Mr. E. Wethered, and Mr. A. 
Strahan, appointed for the purpose of investigating the Rate of 
Increase of Underground Temperature downwards in various 
Localities of Dry Land and under Water. Drawn up by Prof. 
Lverett (Secretary).—TVhe present Report is for the two years 
since the summer of 1883. Observations have been taken in a 
deep bore at Richmond, Surrey, by Mr. Collett Homersham, 
C.E., the engineer of the boring, on the premises of the Rich 
mond Vestry Waterworks, on the right bank of the Thames, 
and about 33 yards from high-water mark. The surface is 17 
feet above Ordnance datum. The upper part consists of a well 
253 feet deep, with an internal diameter of 7 feet at top and 
5 feet at bottom, which was sunk in 1876 for the purpose of sup- 
plying water to the town of Richmond, and carried down to the 
