514 
SCIENTIFIC SUMMARY. 
AGRICULTURE. 
A New Method of Producing an Artificial Manure has been suggested 
to the Academy of Sciences by M. Duponchet. It is in part an applica- 
tion of the ordinary method pursued by Nature. All natural soils result 
from the breaking down of rocks by means of the united action of air and 
water. He proposes to take the lands of Gascoyne, which are now 
almost barren, and to render them fertile in the following manner : 
streams of water containing mud are to be allowed to flow for years over 
the plains (which must he enclosed), and in this way after a certain period 
a stratum of silt will be deposited upon the surface of the land, which, 
when mixed with ordinary manures, will render this part of the country 
productive. The scheme is decidedly ingenious ; but is, we should think, 
of a character not well adapted to its success in a pecuniary aspect. 
The Functions of the Roots of Plants . — M. Henrici has made some in- 
genious and interesting observations on the functions of roots in supplying 
water to the plant, and in the development, under certain conditions, of 
special roots destined for this purpose. It is a matter of not unfrequent 
occurrence, that plants send roots into wells, cisterns, drain-pipes, &c., 
where they exist in continual contact with a body of water. In drain- 
pipes, the roots of plants usually considered to be free from aquatic 
tendencies, such as rape, sometimes accumulate to a surprising extent. 
M. Henrici surmised that the roots which most cultivated plants send 
down deep into the soil, even when the latter is by no means porous or 
inviting, are designed especially to bring up water from the subsoil for the 
use of the plant. The following experiment wa3 devised for the purpose 
of establishing the truth of this view. On the 13th of May, 1802, a young 
raspberry plant, having but two leaves, was transplanted into a large 
glass funnel filled with garden soil, the throat of the funnel being closed 
with a paper filter. The funnel was supported in the mouth of a large 
glass jar, and its neck reached nearly to the bottom of the latter, where it 
just dipped into a quantity of water. The soil in the funnel was at first 
kept moderately moist by occasional waterings. The plant remained 
fresh, and grew slowly, putting forth new leaves. After the lapse of 
several weeks, four strong roots penetrated the filter, and extended down 
the empty funnel neck, through which they emerged on the 21st of June, 
and thenceforward spread rapidly in the water of the jar. From 
this time the soil was not watered any more, but care was taken 
to maintain the supply in the jar. The plant continued to develope 
slowly ; its leaves, however, did not acquire a vivid green colour, 
but remained pale and yellowish ; they did not wither until the usual 
time late in autumn. The roots continued to grow, and filled the 
