10 An Analysis of Sea-waler : 



lowed bv successive currents next the earth in the same direc- 

 tion. 



Yesterday lie iaunched fron"! Cla])ton a middle-sized inflam- 

 mable gas-balloon, at three o'clock P.M., the smoke and wea- 

 thercocks indicating- a W. wind. The balloon consequently 

 went in an E, direction ; but at the height of what on a rougli 

 guess might seem to be above five or six thousand feet, it got 

 into a NW. gale, and seemed carried toward SE. At half after 

 four the smoke from the chimneys indicated the same wind, 

 though so gentle as hardly to be perceived, and which did not 

 move the con)mon weather-vanes. 



The last experiment confirms also an observation which I 

 have before made, Ijy means of the movement of tiie higher 

 clouds; namely, thai: when the therniometer is below the freezing- 

 point with a southerly wind, there is then a northerly wind blow- 

 ing above it. — We have oflfered a small reward for the balloon, 

 and shall be obliged to any person who mav communicate where 

 it fell, that we may ascertain its ultimate direction. 



I hope to communicate in future more accurate details of 

 aeronautic experiments on wind; and I merely communicate the 

 above to excite persons in diflferent places to make corresponding- 

 observations. The small balloons are easily made cf varnished 

 paper; they are preferable to those sent up with rarefied air, as 

 they ascend higher and keep up longer. But the rarefied air- 

 balloons are capable, when made large enough, of indicating se- 

 veral currents of air. 



Besides the above experiments of which I have minutes, my 

 brother has sent up a great many balloons, and has almost al- 

 ways observed them moved by two or three currents : a circum- 

 stance which shows how little these machines (notwithstanding 

 the sanguine assertions of some French writers) can ever be de- 

 pended on as instruments to convey intelligence to armies 

 where the ordinary means of communication may have been in- 

 tercepted by the enemy. I am, sir, yours, ike. 



Walthamstow, Dec. 12, ISl/. T. FoRSTER. 



IV. A7i Jnalysis of Sea-ivater ', wil/i Observntlnm on the Aim- 

 lysis of Sail- brines. By John .Murray, M. D. R R. S. E.* 



T 



J. HE composition of sea-water has been variously stated bv 

 dififerent chemists, not only with regard to the proportions of the 

 salts which it holds in solution, but with regard even to the in- 

 gredients themselves. 



• From the Transactions of the Royal Society of Edinburgh for 1816. 



According 



