APPENDIX. 343 



The number of different currents blowing at the same time 

 at different altitudes, is a circumstance I ascertained by the 

 following experiments : On the 25th Oct. 1809, an inflam- 

 mable air balloon was launched from Clapton, in Hackney : 

 the balloon was made of varnished paper, quite water proof, 

 three feet six inches in diameter, and filled with inflammable 

 gas. The process of filling it was begun at one o'clock in the 

 afternoon ; and by about ten minutes after two, the balloon 

 appearing sufficiently inflated, a small paper parachute was 

 attached to the bottom of it, by means of touch string. It .. 

 was now found that the buoyant power of the balloon was 

 just sufficient to carry the appendage. Upon the touch string 

 being lighted, the balloon was launched into the air. At first 

 it ascended very slowly in a direction nearly W. N. W. and 

 in less than a minute dropped the parachute, which fell into 

 the brick field opposite Hackney New Church. The balloon 

 now ascended more rapidly in the same direction for several 

 minutes, when, being very high, it met a different current of 

 air, and was observed to travel nearly towards the South : 

 this was ascertained by the balloon's getting much more 

 southward without increasing or diminishing in apparent 

 magnitude, which it would have done, if it had taken a 

 course either much to the East or the West of the South. 

 In a few minutes more its course was again altered by a third 

 current of air, which carried it in a direction apparently N.E., 

 when it passed again over the northern part of the parish of 

 Hackney, and was distinctly seen from the place of its ascent. 

 At about twenty minutes before three, it was blown by a fourtli 

 current nearly N. N. W. by N. Thus there appear to have 

 been four different currents above one another, namely, 

 E. S.' E. N. S. W. and S. S. E. by S. It very soon be- 

 came invisible to the naked eye, but was discerned through a 



