Proceedings of the British Association. 371^ 



Thus according to Mr. Whewell's method of taking the obser- 

 vations, (which he was persuaded was the only true method,) in 

 the latitude of Plymouth, they had something like a trade-wind, • 

 setting in from southerly to northerly points of the compass at a 

 mean velocity of 4^ to 6 miles per hour. This was something 

 like a definite result in meteorology ; for no person before had 

 ever attempted to discover the direction and velocity of the winoF 

 in its rate per hour, setting in a given direction.* In these state- 

 ments he had been dealing only with mean results. 



Mr. Howard hoped that Mr. Harris would not think of discon- 

 tinuing these observations until at least the cycle of 18 years had 

 been completed. — Col. Sykes believed that the hours of maximum 

 and minimum mean pressure observed by Mr. Harris at Plymouth, 

 would be found nearly, if not exactly, the same as those obser- 

 ved in India at an elevation of 2000 feet above the sea, and those 

 observed in Mexico, by Humboldt, 10,000 feet above that level. — 

 Col. Sabine said, he had that morning received a very important 

 letter from Prof. Wheatstone, containing a proposal to make, for 

 the Observatory at Kew, an apparatus which should record the 

 operations of all meteorological instruments so as to effect a great 

 saving of cost. One of the instruments was for measuring the 

 force and direction of the wind, and was capable of being sent 

 up in captive balloons, so that the currents, to a height of 8,000 

 or 10,000 feet, might be carefully examined. All attempts to 

 make self-recording thermometers, barometers, &c. by mechani- 

 cal means, have hitherto failed, because the mechanical force ex- 

 erted by the rise of the mercury in the tubes, is insufficient to 

 overcome the friction of the attached mechanism, and only very 

 inaccurate indications can be obtained. The principle however, 

 (observes Mr. W. ) which I employ in my meteorological telegraph, 

 viz. the determination (by means of a feeble electric current) of 

 any required mechanical force by the mere contact of the mer- 

 cury in the tube with a fine platina wire, enables all these diffi- 

 culties to be overcome. I propose, therefore, that such an instru- 

 ment, the cost of which I estimate will not exceed £50, shall be 

 constructed under my direction for the Richmond Observatory. 

 If, after a few months' trial at the Observatory, it shall be found 



* See Prof. Loomis's conclusions regarding tlie progress of the wind at Hudson, 

 Ohio : this Jour. Vol. 41, p. 320. 



