METEOROLOGY. 175 



active and determined observer soon sinks under repeated exertion, and can 

 only be restored by periods of repose. While Man sleeps, Nature works ; 

 and we often find that in a brief space we have irrecoverably lost some im- 

 portant link in a chain of evidence which might have led to important re- 

 sults. These remarks apply with peculiar force to the science of Meteorolo- 

 gy, in which we have to mark the operations of agents so numerous and 

 apparently so variable that they defy the most acute sagacity to foresee their 

 effects, or comprehend their causes. 



Human ingenuity has been busily employed in devising methods to meet 

 this difficulty. Instruments have been invented to make the elements leave 

 a record of some of their most important changes. Thus the self-registering 

 thermometers of Dr. Rutherford and Mr. Six are so constructed that they 

 show the highest and lowest degree of temperature which occurs between 

 any two observations : the new anemometer of Professor Whewell marks the 

 force and direction of the wind between two periods of time. These are im- 

 portant inventions, and will do much to advance our knowledge of meteoro- 

 logical phenomena : but they have one great defect— they register all the 

 changes which have occurred between any two points of time, but they do 

 not mark the precise moment when any particular change takes place. We 

 learn, for instance, from Dr. Rutherford's thermometer, the coldest tempera- 

 ture during the night and the hottest during the day ; but we have no means 

 of knowing the exact time when those degrees of temperature took place. 



This desirable object, as far as concerns the wind and the rain, has been 

 accomplished by an instrument invented by Mr. Follett Osier, of Birming- 

 ham, " The Self-registering Anemometer and Rain-guage," which has been 

 for some time in operation at the rooms of the Birmingham Philosophical 

 Institution, the results of which, united to the daily observations of the ba- 

 rometer, the maximum and minimum thermometer, and Daniel's hygrome- 

 ter, are embodied in the following tables. It may be necessary to explain to 

 those readers of The Analyst who have not seen the self-registering anemo- 

 meter, a few particulars of its construction. In this instrument, the vane, 

 which is about 16 feet in length, is attached to the hollow metal rod which 

 carries it ; consequently, the rod moves with the vane. At the lower end of 

 the tube is a small pinion, which works into an horizontal rack which slides 

 backwards and forwards as the wind moves the vane : to this rack a pencil is 

 attached, which marks every movement in the direction of the wind, on a 

 paper ruled with the cardinal points, and so adjusted as to move forwards at 

 the rate of half an inch per hour by means of a clock. The force or velocity 

 of the wind is at the same time ascertained by a plate, one foot square, placed 

 at right angles to the vane, supported by two light bars running on friction 

 rollers and communicating with a spiral spring in such a way that the plate 

 cannot be affected by the wind's pressure without constantly acting on this 

 spring and communicating its action by a silver wire passing down the cen- 

 tre of the tube to another pencil, by which it thus registers its degree of 

 force. The quantity of rain is registered on the same paper, by its weight 

 acting upon a balance which moves in proportion to the quantity falling. 

 The motion of the balance being communicated to a pencil attached to it, the 

 result is recorded. The receiver is so arranged that when a quarter of an 

 inch of rain has fallen it turns upon its axis and discharges its contents, and 

 the balance being thus relieved from its weight, the pencil returns to zero. 



