SELF-REGISTERING ANEMOMETER AND RAIN-GAUGE. 139 



ber, January, and February. November seems to be the stillest month in 

 the year, and March, which is usually considered such a windy month, is in 

 fact one of the four in which the least amount of motion in the air occurs, 

 while April is only surpassed by the three winter months mentioned above. 



Table Vlll., like the preceding, gives the mean hourly motion of the air 

 without regard to direction, but instead of referring to the months, shows 

 the amount of motion between any one hour of the day and the next follow- 

 ing, as explained in the heading of the table. This is illustrated in Plate XL, 

 a reference to which will render any lengthened explanation here unnecessary. 

 I would merely call attention to the coincidence between these curves and 

 those of temperature ; they also agree in a striking manner with the curves 

 I laid down in a similar way from the observations taken in Birmingham 

 with the Force Anemometer, and which appear in the Report of the British 

 Association for 1840, already alluded to. 



In the foregoirij: Tables in this Report, the horizontal motion of the air, 

 obtained from Dr. Robinson's revolving cups, is tabulated in preference to 

 the force, not only because it can be recorded more definitely, but as afford- 

 ing many interesting results respecting the velocity of various winds ; but 

 when observations from different stations have to be compared, the force 

 register will be found of great utility, by exhibiting the sudden and extreme 

 changes which frequently take place, not only in storms, but in the more 

 regular currents of the atmosphere, when those marked and important indi- 

 cations become of peculiar interest : on this account I consider both modes 

 of registration as desirable. 



Important as are the Observations at the Liverpool Observatory, contained 

 in the foregoing Tables, their value will be much enhanced when regarded 

 in connexion with those at other places ; and this leads me to repeat a pro- 

 position to which I have on more than one occasion taken the liberty of 

 calling attention, namely, the expediency of carrying out Anemometrical 

 Observations on an extended scale, especially further South, where the 

 action of the sun, that great disturbing cause, is more marked and regular ; 

 after this is in operation, the observations may be advantageously carried 

 Northwards to our own country, where the changes are more complex. We 

 cannot hope to determine the laws of the great atmospheric currents from 

 observations limited to such an ever-varying condition of the elements as 

 exists in these islands, which are situated in a region of variable winds pro- 

 ducing an equally varied climate, and lie, moreover, on the borders of a 

 great continent as well as a vast ocean; but if such observations were com- 

 bined with a series of continuous anemometrical records of the atmospheric 

 currents, commencing nearer the equator, I think it would do more towards 

 the advancement of the Science of Meteorology than any other class of 

 observations. 



The very valuable observations that are being taken by Captains of vessels 

 carrying meteorologii cd instruments supplied by Her Majesty's Govern- 

 ment, under the management of Captain Fitzroy, as well as those from the 

 American Government, under the superintendence of Lieutenant Maury, 

 are of great and immediate practical value ; but I am of opinion, that 

 if a number of standard points were to be selected, and a continuous series 

 of self-registered observations obtained, the investigations that are now going 

 on would be greauly benefited and advanced. Detached observations 

 on the wind taken at intervals on board ship, are most valuable in filling 

 up the spiices betwcrU fixed and unerring self-recording instruments, but 

 are scarcely sufficient to procure such exact knowledge of tiie variations 

 as it is so necessary to obtain, if the movements of the air are to be 



