Mr De La Eeche m the Depth of the Lake of Geneva. 107 
in his late Flora of that country. Still, it is perfectly possible 
that it may have been overlooked. 
Whether this species be known on the Continent of Europe, 
does not clearly appear. It may be noticed, however, that the 
Rosa prostrata of the last edition of the Flore Fran^aise, is de- 
cribed as distinguished by its ‘‘ shining persistent leaves,” 
characters quite applicable to the Ayrshire Rose. 
Canonmills, ) 
im Nov. 1819. j 
Art. XVIII. — On the Depth and Temperature of the Lake f 
Geneva. By Mr H. T. De la Beche. Communicated by 
Professor Pictet With a Map. 
I HAVE the honour of communicating to you some observations 
on the depth and temperature of the Lake of Geneva, which 
the goodness of the season has permitted me to make. 
The accompanying map (Plate II.) points out the places 
where I sounded, and the corresponding depths. These depths 
are greatest on the coast of Savoy, till opposite Lausanne, where 
the lake becomes deepest on the side of the Canton de Vaud. 
The places where the banks descend most rapidly, are the 
point of Drances, Meillerie, St Gingoulph, the Castle of ChiL 
Ion, and Vevay. In several places, the greatest depths occur 
about 50 fathoms from the shore, particularly at St Gingoulph 
and Vevay, where the bottom again rises. 
The soundings were taken with two cylindrical masses of lead, 
one of which weighed 10 lb. and the other 8 lb. The weight of 
8 lb. was sufficient for the greatest depths, and was able to re- 
sist every current. 
These currents did not frequently occur, and those which I 
did observe, had little velocity, excepting in the sounding of 80 
fathoms, opposite the Point of Drances, where no sensible current 
* The observations in this paper were addressed by their author to Professor 
Pictet, for the Bibliothe^ue Universelle. We have abridged the preliminary re- 
iparks. — Ed. 
