New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1874-07-27

plete misunderstanding of the facts related Dy Dim'
and of the general conclusions of other students
especially those of MuhTy. could lead one to believe
that the influence of the forests can be only nslg-
nfcant upon cimatology, and especially upon the
cultivation of the soil; the preservation OF forests
must therefore be considered as an object worthy OF
most serious consideration and earnest national en-
terprise. Within the foliage the moisture OF the
atmosphere is condensed; and in consequence OF
complicated process, it results that from the upper
surface of the foliage off forest cold air flows down.
This air slightly raises its temperature, ana pre-
serves the earth in the interior OF the forest AT
temperature several degrees higher on the average
tnan that which Is not protected, Inc forest, III
fact operates i'll manner very similar 10 the ocean
or n large lake. As the sea-wind blows upon land
during the daytime, during the daytime the cold
air of the forest blows ont toward the free space AS
the lard wind at night flows toward the ocean, so IN
the evening the cold air III the forest receiving the
warmth OF the warm EARTH rises up, Whle the cool
arr from the exterior region loWs IN 10 take us
place. This daily vertical cOmpensatihg circulation
has an intensity proportional To the extent OF the
forest and the barrenness of the soil that Is rot pro-
tected. In regard TO the formation OF nan he con-
cudes that il is determined by the conditions exist
ing in the upper regions of the arr but the direction
OF the movement of the hallstorm ana It's variable
intensity from point TO point are principally deter
mined by local influences, and especially the yert-
cal currents of the atmosphere that depend Tor their
existence upon the presence OF forests hea'ed pahs
rivers DC.
INCREASING THE SENsITIVENEss TO LIGHT OF
BROMIDE OF SILvER.-The researches OF Nogel on
the sensibhty of bromide OF silver TO the rays Of
light were sometime ago briefly noticed in these col
umns, but the original article by himself has lately
come to hand. The insensibility of bromide of sill
yer to certain colors of the spectrum is weknown
fact as also its peculiar sensibllty to Invisible ultra
violet rays Vogel has shown that the sensibilty Of
this preparation may be carried far into the red end
of the spectrum to regions where hitherto photog-
raphy has been impossible. Vogers attention seems
first to have been called to this subject by receiving
some dry sensitive plates from England which
proved to be more sensitive to the green than TO the
blue rays and, in general, he found that the dry
bromide exhibits n more extended sensiblllty for
colors than does the so-caed wet plate. This sensi-
tivenese however was much affected by the method
of development. In attempting to prepare bromide
of silver plates with his hands, he found no re-
petition of the phenomenon which he had noticed
on the English plates; and easJning upon the sub
iect he conectured that the English plates must
contain some substance that absOrbS the green rays
in 2 greater measure than the blue Noticing that
the English plates contained among other things,
yellow coloIlng matter as n coating he made an at
tempt to impregnate bromide of silver with q sub
stance that should absorb especially the yellow rays
The substance he chose was cOraiine dissolved IN
!
decided red tint. and exposure 10 the spectrum
they proved specially sensitive IN the indigo ana IN
the yellow, and Of diminished sensitiveneSs IN the
| intermediate portions of the spectrum. mus a
method was attained OF preparing bromide or SILVER
plates thar acted upon almost as stfongy.Dy Il
color hitherto held to be chemically inert, namely,
veIloyy "a they were by the indigo blue PTOcceG-
ing further in his experiments he found among the
green anilinc products. body endowed Win pow
crfu absorption of red rays. by means OF winch ne
heightened the scnsitveneas Of his bromide plate TO
that color. From these results he THINKS he !, wei
justified in inferrng that we are IN position u rem
der bromide of silver sensitive to any color that we
NAV choose. These experiments. both In practical
and theoretical point of view cover somewhat an
frrent field from those Of DIR. Draper OF New-lorA.
who 81 years demonstrated that any color W!ia
ever could be photographed by employing properly
selected chemical for preparing the sensitive pi'e'
TIE REDUCTION OF BARONCTEC OBSERVATIONS
TO TIE SEA LEyEL.-Ihe recent publication 10y DE.
Ham of a short essay in which he throws great
doubt upon the propriety of the Ordinary methods OF
reducing barometric observations to sea level. and
even virtually Acknowledges that il Is impossible 70
effect this reduction without introducing gross
errors, has had the effect Of drawing from Wild Of
ST Petersburg and from Jenek Of Vienna two most
interesting aud valuable statements Of the reasons
why they prefer to continue TO adhere TO the meth
ODDS recommended by the Vienna Congress ia 1873
The method proposed by Wild. which he states has
recently been adopted by himself for all the Russian
observat atoms, is a somewhat peculiar mixture OF
three different methods adapted 10 three different
classes Of meteorological stations. and apparently
the objections that be urges 10 De- Hams pro-
positions amount simply to tlis that The So
called deviations between the individual and the
normal values of barometnc pressure require them
selves to he reduced to sea level, although this al
present is rarely or thought of. and that in
this reduction errors woad necessarily be introduced
perfectly comparable IN their Importance 10 those
incident to the best methods of reducing the barom-
etric pressure itself The methods proposed by him
are evidently applicable within moderate limits OF
error only to such systems of observation as are in
vogue III Europe where but one daily report is sent
to the central station and are TO far less degree
apDiicable 10 the system of tTl-daly observations
| carried on in the United States. lu Jelinek ;
opinion the strongest Argument IN favor
reduction to level consists in securing thereby
uniform method i'll meteorological uniformity that
seems to him so extremely valuable that other con-
siderations must sometimes be made 10 stand aside.
As to the details of the Application OF TN, method.
| he agrees with Wild IN perhaps everything except
that he would prefer me Laplace iane' TO Ihose OF
higher degree of theoretical accuracy. H therefore
urges its exclusive application III all Geographic
| weather reports.
| From Jclineks communication. as we'll as that Of
| Wild, it Is evident. however, that the needs OF
European stations are far different iron those on
| this side of the Atlantic. de states in fact, that
elevated stations will never furnish data that can he
comparable with those given by the stations nearthe
| level of the They must therefore, not he APP
piled in making use of Geographic weather reports,
and this is also the with stations thar stu
ated in localities subject 10 peculiar anomalies Of
temperature. When. however II is necessary 10 use
| these observations because there none at hand
from stations situated at lower atitrde then the
| data in question must be made use of in method
| quite different from that employed for the coast
| stations, namely, only as indicating the changes
| gong Oh in the middle layers of the atmosphere.
| MErEoRoIoGY N RUssIA.--The last Report of the