190 
the daily change of temperature, produced by the aggregate of 
strictly diurnal change (depending on the solar hour) and tidal 
change (depending on the moon’s apparent position) is so small 
that it is impossible to attach with any certainty a sensible value 
to either of these causes. 
I now proceed to describe the principal steps in the reduction 
of the observations. 
In the weekly publication of these observations by the Regis- 
trar General, the weekly means of each observed element were 
also exhibited. In preparation for a detailed publication of the 
whole, I had the entire series of these weekly means collected, 
each being accompanied with notes of the principal phases of the 
moon, the occurrence of remarkable storms, &c., occurring 
within the week. (This vészé exists, and is available for any 
discussion which might be suggested ; I propose to offer it for 
deposit at the Royal Observatory.) But on general examination 
of the collected means, I did not perceive that any result could 
bz expected which would justify the labour and expense of 
printing the whole. For instance, if there were any re- 
markable dependence on the phase of tide, different values 
for the ‘‘excess of mean temperature of the water above 
mean temperature of the air” would occur in the weeks which 
included respectively new moon, first quarter, full moon, third 
quarter, and these would recur with little alteration for several 
months. But on general examination, I do not see anything 
which would justify more technical discussion directed to this 
point. Finally I decided on exhibiting only the means of de- 
ductions as to temperature for each calendar month, and omitting 
all other phenomena. As the succession of weeks and the suc- 
cession of entire months do not generally coincide, the rule was 
established to adopt the first entire week in each calendar month 
as the first of the weeks to be used, in conjunction with three or 
four weeks following, to form the monthly mean. Thus, some 
months contain four weeks, and some contain five weeks. For 
instance, the month of March, 1846, contains the five weeks, 
March 1-7, 8-14, 15-21, 21-28, 28-April 4 ; but the next month 
contains only the four weeks—April 5-11, 12-18, 19-25, 26-May 2. 
By this system, the results, as far as they appear to possess 
any value, are brought into the compass of five convenient Tables 
of Double Entry, which, with their columnar and lateral means, 
appear to give all the information that can be desired. The 
contents of the several tables are :— 
Table I. Monthly Mean Temperature of the Water of the 
Thames. 
Monthly Mean Atmospheric Temperature at the 
Royal Observatory. 
Monthly Mean Excess of Thames Temperature 
above Observatory Atmospheric Temperature. 
Monthly Mean of Diurnal Kange of Temperature 
of the Water of the Thames. 
Monthly Mean of Diurnal Range of Atmospheric 
Temperature at the Royal Observatory. 
The last line only of each of these tables is given in the present 
communication to NATURE. 
Table II. 
Table III. 
Table IV. 
Table V. 
Monthly Means, through a Range of Thirty-five Vears, of the 
Principal Elements of the Temperature of the Water of the 
Thames 
| | 
Excess of 
Mecn ere Atmo- | tempera- Di ! Diurnal 
ae «| SPheric | ture of the eae range of 
Mont [Phe water | tempera- | Thames | Tange 0 atmo- 
avLonth. © water ture atthe! above at- Renee | spheric 
| apne. | Royal Ob-| mospheric "Th, of the | tempera- 
MES. | servatory. ais DES AT rare 
ure. 
° ° ° ° | ° 
January ... ... 39°4 389 +0°5 1'9 96 
February 40°7 40°4 +0°3 2 OM eeule5 
Marebir 32.0 43°6 42°8 +0°8 EKO }| si Os) 
Aiprile) G20": 50°0 48°7 +1°3 Be 18°5 
May 56°3 54°4 +19 2 19°9 
June 62°6 60°6 +2°0 232, 5 j|/zo:5 
ulyxce, ce ci 65°7 63°9 +18 2%. | 2152 
August ... ... 64°4 62°6 +1°8 2'0 19°6 
September ...| 59°9 579 +2°0 UGie ieetosk 
October... ... | 52°9 507), | +272 Zi0)) Ne Ang 
November 44°3 42°3. | +2°0 21 a mS, 
December 404 | 393 | +06 2:0 gi dote 
| 
NATURE 
[ Dee. 21, 1882 
And the following appear to be the legitimate epitomised 
inferences :— 
(1). The mean temperature of the Thames-water is higher 
than that of the Observatory thermometers by 1°°5. But the 
locality of the Observatory thermometers is, in hypsometrical 
elevation, about 160 feet above that of the Thames thermo- 
meters. It would seem probable therefore that the mean tem- 
perature of the water is higher than the climatic temperature by 
only a small fraction of a degree. 
(2). This difference is not uniform through the year. With 
some irregularities, the greatest excess of Thames temperature © 
occurs in September, and the least in February. But the 
autumnal difference exceeds the spring difference by only 1°°6. 
It seems not improbable that this is the effect of a slight commu- 
nication with the sea, whose surface-waters have accumulated in 
autumn the effect of solar radiation through the summer; with 
contrary effect at the opposite season. 
(3). The mean range of temperature through the day is 
2°*r, And this expresses the numerical change from the 
lowest solar temperature, or the lowest temperature in the 
first tide, or the lowest temperature in the second tide (which- 
ever may be the lowest), to the highest solar temperature, 
or the highest temperature in the first tide, or the highest tem- 
perature in the second tide (whichever may be the highest), It 
is evident that the change of temperature due to the diurnal 
change of solar action, and the change of temperature due to 
each of the tides, must each, individually, be very small. 
(4). It appears to me that the fundamental inference must be 
this: that the material water is very little changed at Greenwich 
by the tide. Although a vast body of water rushes up at every 
flow, running with great speed, and sometimes raising the sur- 
face by 20 feet, yet nearly the same water runs down at ebb, 
and is again brought up, with all its contents, at the next flow. 
These expressions are to be taken as modified by the descent of 
fresh water from the land; but the amount of that water must 
be small, in comparison with the mass which it joins in the 
Thames at London. 
(5). Ido not imagine that the tidal action has any beneficial 
effect on the climate of London, except that probably the 
agitation of the water produces mechanical agitation of the air, 
and thus destroys injurious stagnation. 
Mathematical Society, December 14.—Prof. Henrici, 
F.R.S., president, in the chair.—Messrs. T. Woodcock, Hugh 
Fraser, Major Allan Cunningham, R.E., and Capt. P. A. 
Macmahon, R.A., were elected members.—The chairman 
announced that in consequence of ill-health Mr. C. W. Merri- 
field, F.R.S., had been obliged to resign the office of treasurer, 
and that the council had elected Mr. A. B. Kempe, F.R.S., to 
undertake the duties of the office. Dr. Hirst spoke in feeling 
terms of the work Mr. Merrifield had done for the Society, and 
in accordance with his suggestion a vote of thanks for his 
services in the past, and of condolence with him on account of 
the reasons which had led him to sever his official connection 
with the Society was carried.—The following communications 
were made :—On the vibrations of a spherical shell, by Prof. H. 
Lamb.—On the absolutely least periods of the elliptic functions, 
by Prof. H. Smith, F.R.S.—On certain relations between 
volumes of loci of connected points, by Mr. E. B. Elliott.— 
Geometrical proof of Griffiths’ extension of Graves’ theorem, 
by Mr. J. J. Walker.—On polygons circumscribed about a 
tricuspidal quartic, by Mr. R. A. Roberts.—Note on an excep- 
tional case in which the fundamental postulate of Prof, Syl- 
vester’s theory of Tamisage fails, by Mr. J. Hammond.—On 
certain quartic curves, which have a cusp at infinity, whereat 
the line at infinity is a tangent, by Mr. H. M. Jeffery, F.R.S. 
Zoological Society, November 28.—Prof. W. H. Flower, 
F.R.S., president, in the chair.—Mr. W. B. Tegetmeier ex- 
hibited and made remarks upon the skull of a rhinoceros from 
Borneo; also the horns of a buffalo and deer from the same 
country.—Mr. J. E. Harting exhibited a specimen of the South 
African Eagle-Owl (Budo maculosus), said to have been obtained 
many years ago near Waterford in Ireland.—Mr. R. Bowdler 
Sharpe exhibited and made remarks on some specimens of 
Swifts from the Congo. Mr. Sharpe also exhibited a specimen 
of Macherhamphus alcinus which had been obtained in Borneo 
by Mr. Everett.—A communication was read from Prof. Owen, 
C.B., on the sternum of /Vofornis and on sternal characters.— 
A communication was read from Dr. A. B. Meyer, C.M.Z.S., 
in relation to the adoption by naturalists of an international 
#7 a?) er 
