To the Editor of the Carlisle Patriot.

Sir, - I have observed with much satisfaction that the usefulness of your
valuable paper has of late been greatly increased by a judicious selection
of matter connected with the agricultural productions and improvements of
our native soil.  But my principal motive for troubling you at present is to
suggest a few crude hints tending to illustrate and explain the agency which
may be supposed to produce the extraordinary effects ascribed by MR. GURNEY
to a "Fibrous covering on vegetation."  In an extract from a very able and
interesting letter on this subject by DR. VACY, of Launston, given in your
paper of the 6th Sept., the results of various experiments are fully
detailed;  but with regard to the agency producing these results, the
learned doctor admits that he could say little, as "they seemed to involve
difficulties in the solution of problems connected with vegetable physiology
supposed to be solved by received theories."

Now, I would beg leave to suggest that moisture is the active agent in this
case, as, indeed, in most others, for promoting and encouraging the
developement of the vegetative principal.  Thus we see grass growing
luxuriantly on the margin of brooks, on irrigated meadows, and other set
situations;  and also in shaded places, where the nourishment afforded by
the dew is longest continued.

It may be remarked, also, that in such situations there is an openness and
looseness in the soil particularly favourable to vegetation.  But as more
immediately connected with this inquiry, I may notice also another, and
perhaps even a more efficient agency, constantly at work in a copious
evaporation arising from the surface of the earth, the escape of which is
greatly obstructed by the covering, and being condensed, is retained for the
nourishment of the plants underneath, which otherwise would have been
dissipated and lost in the atmosphere.

This covering, however, should not be so thick as to exclude the beneficial
effects of rain and dews, nor so thin as to suffer their influence to be
destroyed too hastily by evaporation afterwards.

The utility of the covering, whether of straw or brushwood, does not, I
presume, consist in its action as a manure, by adding fertility to the soil,
but merely as being instrumental in preventing the escape, to a certain
extent, of such a quantity of moisture as may be requisite for promoting and
sustaining the rapid growth and luxuriance of the grass.

The policy of a full and fair investigation of this important subject DR.
VACY strongly urges upon the notice of the agricultural public, and I trust
it will not be overlooked by some of your correspondents of attainments
superior to

                                    Your obedient servant,