ADDRESS. lvil 
ficient to furnish such a connected knowledge of the subject as would enable 
us to follow the course of the tide over any considerable portion of the ocean, 
and in the opinion of persons most competent to judge, it is only by systematic 
observations specially directed for the purpose, that this connected knowledge 
is likely to be obtained. Accordingly a resolution was passed at the Ipswich 
Meeting of the Association, appointing a Committee to prepare a Memorial 
to Her Majesty’s Government, representing the importance of determining 
the progress of the tide-wave along the coasts of Africa and South America 
by an Atlantic Tidal Expedition. This Memorial was presented to Govern- 
ment by my predecessor, and, having been referred to the Hydrographer, has 
been most favourably reported upon. We may therefore expect that the 
survey will be very shortly commenced. The recent researches of Captain 
_ Beechey, which have given a new and unexpected view of the tidal movements 
of the ocean, show how much yet remains to be learnt respecting the tides 
even for the practical purposes of navigation. 
_ The facts derived a few years since from the barometrical observations at 
St. Helena, showing the existence of a lunar atmospheric tide, have been 
corroborated in the last year by a similar conclusion, drawn by Captain Elliot 
of the Madras Engineers from the barometrical observations at Singapore. 
The influence of the moon's attraction on the atmosphere produces, as 
might be expected, a somewhat greater effect on the barometer at Singapore, 
in lat. 1° 19’, than at St. Helena, in lat. 15° 57'. The barometer at the 
equator appears to stand on the average about 0006 in. (more precisely 
0°0057, in lat. 1° 19') higher at the moon’s culminations than when she is 
six hours distant from the meridian. 
We have received from our valued corresponding member Prof. Dove, for 
presentation to this Meeting, an important continuation of his researches on 
the temperatures at the surface of the globe. In former communications he 
has furnished us with maps showing, so far as observation permits, the 
: isothermals of the whole globe in every month of the year. He has now 
_ given us, first; the normal temperatures of each parallel of latitude in each 
P month; being the average of all the temperatures in that parallel in such 
- month; and second, the abrormal temperatures, or the difference between the 
1 temperature of each place and the mean temperature of its parallel. From 
- these again are formed lines of abnormal temperature for each month, sur- 
_ rounding and marking out those districts or localities, which, from peculiarities 
_ of the surface or other causes affecting the distribution of heat, are charac- 
"terized by excessive abnormal heat or abnormal cold. The importance of 
_ these researches on the general theory of the causes which interfere with the 
equable distribution of heat according to latitude is obvious. 
_ The activity which has prevailed so greatly of late, in the collection 
of meteorological data, has been almost exclusively confined to that portion 
of the surface of the globe which is occupied by land, although the portion 


