Aeronautics applied to Meteorology. 9 



chartered companies, we have seen usurped and persevered in to 

 an improvident extent. Hence it is these instruments of ana- 

 lysis may remain dorn.ant as speculative truths, till, by the ac- 

 cession of more copious and efficient auxiliaries, the practical may 

 be said to keep pace with the mathematical means. 



Having been prevented by particular circumstances from pay- 

 ing earlier attention to this matter, if you will have the goodness 

 to allot it a place in the next number of the Philosophical Ma- 

 gazine, it will confer an obligation upon, Sir, 



Your obliged and humble servant. 

 Haberdashers' Place, Hoxton, J AS. Benj. BeNWELL. 



December 12, 1817. 



HI. Aeronauiics applied to Meteorology. By T. Forster, Esq. 

 To Mr. Tilloch. 



Sir, — X HAD for a long time suspected, from the direction of 

 the flying clouds, that the currents of air which occupied the 

 higher regions of the atmosphere came down afterwards, and 

 blew over the earth's surface in tlie same direction as they had 

 previously blown above. To ascertain this fact, I observed at- 

 tentively the various directions of small air-balloons made and 

 sent up by my brother; Out of more than twenty experiments, 

 I have selected the following as confirming this fact : — they were 

 made in different years, and in different times of the year. 



in October 1S09, a gas-balloon three feet seven inches dia- 

 meter, on ascending, first moved with an E. wind; at the height 

 of {about) 500 feet it got into a NN.VV. current; and lastly, at 

 a much greater hltitude got into a strong gale from SVV., which 

 carried it into Cambridgeshire. The succesive changes of the 

 wind next the earth as indicated hv the weathercocks were E., 

 NNW., and SW. 



I have minutes of nine experiments made during the two con- 

 sequent years (18 10 and 1811), in which each balloon got three 

 currents, whose directions became successively the directions of 

 the currents next tlje earth within the space of thirty-six hours. 



In four other experiments made in the same years, two of the 

 balloons went uniformly in one direction, and the wind remained 

 steady for several days. The other two experiments failed; that 

 is to say, the currents indicated by them did not come down, 

 or else they came in the night-time, and were unobserved. Of 

 late years, not being stationary in one place, I have not made 

 so many experiments ; and I have only accurately observed four 

 balloons made by my brother, whereof three got four, and the 

 other got two currents of air : out of these only two were fol- 

 lowed 



