New-York tribune., 1879-11-08
SCIENCE tOR The PEOPLE.

FORESTS AND METEoRoLoGY.-An important
paper PolybibhOn this subject gives the results OF
observations made during the last six years under trees
and not far from the edge OF forest and also IN the
plain and far from all trees 1. Forests Increase the
ouantity OF meteorio waters which fall the ground
and thus favor the growth OF springs and OF underground
waters O. In a forest region the ground receives
much and more under cover OF the trees than the
uncovered ground OF regions with little OF no wood B.
The cover of the of forest dnninshes to large
degree the evaporation Of the water received by the
ground and thus contributes TO the maintenance OF the
moisture the latter and TO the regularity Of tho flow
OF water sources. 4. The temperature In forest is
much less unequal than In the open. although on the
whole it may little lower but the minima are there
constantly higher and the lower than in regions
mol covered with wood These observations have been
made iu the neighbOrhood OF Nancy and by the pupils
of the Forestry Of that city, under the drec
lion OF NJ Mathieu sub-drector OF the school On the
other hand NJ Fautrat. when subuspectOr OF forests
AT senlis made during four years. but different
method, observations on forest metcoroloGy which
fully aud completely c0rrOborae IN certain respects those
NJ NJ uatDien The laws which snem to follow from
The figures gwen by VI. Fautrst as well as an inspeo-
ro M ina cnryes wn IN graphically represent them are
a. follows: l. II rains abundantly under identical
,nd and most abundantly over forests with trees IN
green condition 3 The degree OF saturaton OF the mir
by moisture Is greater above forests than over non
wooded ground and much greater over masses OF pnus
svlyestris than masses OF eaved epeclrs 3 Ine
eafage ana branches OF eafed trees intercept onethrd.
and those resinOus half OF the water.
Vcn aterward returns TO the atmosphere by evapora
ton. Ou the other hand, these same leaves aud
branches retain Tie evaporation OI the wafer Which
reaches the ground, and mat evaporation is nearly four
tunes less under mass OF eaied forest than III the Vpen
and and one third times only under mass OF pines
A. The laws OF the change Of temperature out OF and
under wood similar TO those which result from the
observations Of NJ Matblen; Inc general coneIuslOn
Gems 10 be forests regulate tAe function OF water
and exercise on tue temreraiure az on the atmosphere
AN effect Of "pOnderatlOn" " and equilibrium.
supposng it to be required TO produce copies OF let
ter according to this invention, the letter Is written IN
anlnc INK aud IL applied face downward 10 the
elastic -lab and pressed npon it by light rubbing of
the hand the back of the letter This being done
the removed and the slab then ready to give
of copies OF the letter For TINS purpose DRY sheets OF et-
ter paper provided and applied one after The other
TO The slab which. through gentle rubbing Of the back
the writing. This may De repeated In qucs sueeesNlon
and from seventy 70 "A hundred copies may be obtained
from the transfct wnen the requisite number of
copies has been produced II Is only necessary TO wash
slaD with wet sponge. aud will then he ready for
before The anime In concentrated state is
combined with meihyl lated spirit gun aIanie aud dis
does not give the proportions
ENGRAVING COPPER ROLLERS Copper print
ms-roIlers usually engraved IN two ways. oil
which the impression OF the pattern By means of steel
die process which sometimes. Ia the OF heavy
furniture patterns Is supplemented by direct engraving
with CRAVING tool by hand The other plan etching
The OF the copper being eaten away by tho
application Of acids TINS process gives nice shading.
and nen judicious'y employed Is of much Gene
rally his method consists In covering the roller with
mastic or van.b which protects the places which are
not 10 be acted upon and which leaves the pattern To
I've engraved open. The roller tnus pr pared then
plunged bath Of nitric acid Of 10 Is, or stronger
sometimes little hydrc-chloric acid Is added fuvor
the d.sOlvng action OF the acid The operation gene
rally takes not than five or six mnntes. THIS pro-
cess has grave lnconvemences. especially In places
where there Is sufficiently strong ventilation TO
carry of at once fumes which are formed IN large
ouautites THIS free acd not only dangerous the
workpooplc bur, spreading Ia the room. af cts
me There also tbis draw back. that the
acid acis underneath the Narui-b, resulting unc.rau
edges OF the engraving A German chemist has for
some time employed CHI omio acid IN place Of nitric acid