, 1866-08-21
THE AMERICAN SCIENTIFIC ASS0.
CIATIUN.
The Fruit nclt OF Michigan and the
ser1wln of prElric4.

The Fruit nclt OF Michigan and the
Origin Of Fra.irIcs.
At The session Of the American Scientific
Association at Buffalo last week, Professor
Winehcll read letter On the fruit producing
belt Of Michigan.
The equalizing climatic influence Of the
great lakes upon the State Of Michigan and
especially upon the western slope, was re-
marked By the speaker. Lake Michigan. .
bo*y Of wnter three hundred nnd 1ltty miles
lang ard an average Of seycuty-1yc miles
broad. with a depth of about nine hundred
feet, II enabled 10 preserve something of that
uniformity Of temperature which character
zcs the orCan, and cxcrts similar influence
upon tie contiguous lands. The temperature
In the open lake never riscs above furtr-ilyc
Or iiftg degrees, and probably docs not sink
below ~ thirty, ts five Or forty. Ihe great body
The winds moving over its surface are conso-
Quently warmed In cold weather and cooled
i'll warm The speaker had directed special
attention to the winter climate. Ills ob$cr-
region possessed a uniformity Of tc1npera-
turc not enjoyed by other sections. During
the scrcrest weather Of winter he had noticed
that at Traverse the thermometer showed a
more favorable temperature than several
other localities on the eame parallel. His In
Traverse Bay region is most 1ayorably sit
| untcd Tor drawing out the utmost capabilities
Of the soil, and be doubted whether ans other
portion Of the United States, cast OF the
Rocky Mountains, will be nblc to compete
with it Ia the production Of fruit
on THE ORIGIN OF pnAlR1Bs.
The follo~in. is m abstract Of an interest
ing paper on "The Origin Of Prairics," read
ty Professor ]. S. NewberTy on THURSDAY:
Dr.. ScwbeHy said that great diversity Of
opinion existed us to the Causes which had
produced over half our continent growth Of
forests, and over the other half only on lcr-
bacious vegetation, but in this. as in SO many
world, ifthc disputants could meet on com
mon ground, and each study the phenomena
! observed By Others, and not exclusively his
own data, there would be comparatively lit
tic discord- Tic had spent some years on the
| prnitics In various paris Of the far West, and
| he felt confident that any ono who would 20
over the ground he had tTayeIsed would nsrec
with him that the presence or absence Of for
csts as general rule depended on the amount
Of rrecipitated moisture. The central poE-
tions Of this continent, rs Others, was COM
parativc1y dry, aud was consequently trcc-
| Ices, except on tho nlountain belts, which
acted rs condensors, and precipitated an
amount Of wafer which sustained forest
growth. The rain-fan rsos greater in that
part Of the continent cast Of the Mississippi,
| and here We have almost an uubrokcn forest.
AlonE the line where the tree1ess and for
est districts meet, local causes determine the
presence or absence Of trees. Belts Of tilu-
Der hordcrcd the streams and covered the
more rortous and absorbent soils-whilc level
surfaces, with . fine and unporious soil
sometimes very vet und sometimes very dry,
sustained only a growth Of grass, which
could anlu1e their alterations. fatal 10 trees.
: Annual fires had their influence In extending
the ARIA Of grassy surface, and over much oi
! this middle ground, by nuns Intervention,
the causes limiting the growth OF trees could
. be removed and their forest area extended
SHSAfT L.
and slight cnuscs would make one or tht
other prcpondesatc- The many theories
!. which attributed praIrics TO other causes
tl.an the want Of water were wholly crrono
Gus Of only local value On the great 1,1airic;
9 west Of the Mississippi, every variety Of sol
Z anu surface failed to sustain trecs, and thc.,
u on.s change Of climatic conditions wuult
cnansc ahe EtAsS-coycrcd suriacc to forest.