New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1883-04-01
SCIENCE FOR THE PEOPLE.
SLIPPING OF LOCOMOTIVE WHEELS.


M. Poisot lately communicated to the S0ciet6
de rIndustlie Min&'ate de Saint Et,enne some
useful information as to the means Tor pre-
venting the Shipping of locomotive wheels in
the Mazenay mines, no more fue being en-
ployed for hauling ont 100 tons now than
eighty formerly. He observes that the VEN
tiiation is effected by diffusion, and there is
constantly in the rolley way toleraby thick
smoke, which with condensed steam from the
engine and the dampness of the workings
causes the rails to be slippery. TIE ccnse,,
Quence is that every time they tried to ascend
the gradient of l in 66 with full train, they
could only get up half of IT, about $50 metres
$50 feet-without the wheels beginning TO
spin; and during the rest of the iise notwith-
standing the use of fine and dry sand, this
difficulty frequently began again, so that they
lost pressure to such an extent that they were
obliged to stop TO make steam. Tins diihcuiy
caused great consumption of fuel, excessive
wear of the working parts of the engine, anu
n rapid destruction of the rails.
About two months ago the joint of one OF
the cylinder cocks leaked, and jet OF steam
escaping from it, was directed on 10 .ile 'a ,,
when the train took the gradient without tlie
engine once slipping. For two days usy
worked without making the repair ana the
locomotive drew all the trains WITHOUT ,le
slightest stoppage. In consequence OF tlis
experience they altered the cylinder COCKS SO
as to make them discharge directly on to the
rails. and when they get to the grauleDt 'I'e
cocks are slightly opened, so that tnsy as'e9o
ii without difficulty. Arrangements LOT WASH
ing rail- with Jet of water are very old' nav
ing been used on some OIL Inc + rench INES
fifteen or sixteen years ago. The use OF steam
for the nurpose is simpler modification OF an
old idea.
CITIES WARNER THAN THE COUNTRY.
Those ,,ho happen to live at little distance
from the heart of city, says Science must ire
nuently have noticed lack of accord between
the readings of their own standard tbermome-
ters and the published observations OF the
Signal Service observer of their locality. The
reason of the discord is plain; viz, the perturb-
ing action uf the heat which the city emlts /;
and. however gratifying it may be to the out
slider to find himself superior to the Govern
ment observers, it is very little to the credit OF
the Weather Bureau that this particular source
of error was not long since recognized and
avoided. The remarks OF Professor w Whitney
on this subject as applied to observations mad"
Mt London, are pertinent aud convincing. He
saws: @If is A well known tact. that cities a:e
considerably warmer than the more thnly IN
habited country, otherwise under similar ell
matt conditions. Statistics prove this to be
true: and there could be 10 doubt that such
would be the effect of an immense aggregation
of population within limited space, even II
there were statistics bearing on TINS ques-
tion Many millions of tons of coal are burned
In and about London during every year and
the whole mass of brick OF which the city Is
built Is heated during the entire winter, and
more or less in the summer, many degrees
above the natural temperature. There can De
no question that conditions such as are mere
indicated vitiate all observations made III or
near large cities. with view to the determlna-
ton of any possible secular variation OF the
temperature"