The Locomotive - Lighthouse Survival Blog

1901.] THE LOCOMOTIVE. 47
why the epidemics invariably cease when the average temperature of the air falls below
70° Fahr. For we know that the insect cannot live in clean places, nor in a cool atmo-
sphere.
Other malarial diseases have been stamped out in certain localities by planting
eucalyptus trees, which by their rapid growth and greed for moisture drain swampy
places, or by the artificial draining of swamps, thereby making it impossible for certain
species of mosquitoes, whieh are the carriers of the fever, to exist in these localities.
We cannot, however, as yet explain in what manner the virus is transported over great
distances of land or sea, distances too great for the culex to traverse. We must look
for an explanation in the results of experiments which will determine what is the specific
virus and what is its origin. For it is very plain, almost self-evident, that it is not a
bacillus or coccus. It must be ascertained whether or no the eggs and larvse of the
infected mosquito (for it is only the female insect which sucks the blood of animals)
carry within them the specific poison in a latent form, to become potent in the fully de-
veloped insect, and if so what are the most favorable conditions of climate, temperature
and surroundings for the development and life of the insects. Finally, we must learn
what is the most practical and effective method of destroying the insects and their
eggs and larvae.
When these questions have been answered we will be able to stamp out yellow fever
and a number of other epidemic and endemic diseases, and make the so-called "foci "
of such diseases as yellow fever in Havana and the West Indies, and cholera in India,
salubrious instead of disseminating depots of scourges for the whole world.— Scientific
American.
The late General George B. McClellan, U. S. A., is credited with having made the
statement, many years ago, that the sinking of clams into the sand along the ocean
shore by closing their shells and ejecting the water from them in a thin stream, first sug-
gested to him the use of the water jet as an aid in sinking piles in sand. At any rate,
as long ago as 1852 a water jet was so used, by General McClellan's advice, in putting
down piles for a wharf and warehouse. Water was forced through an ordinary rubber
hose, with a piece of gas-pipe on the end for a nozzle. This was placed close to the
point of the pile on the bottom, the jet of water scouring the sand away from the pile
and making a hole in which the pile sank rapidly. From that time on, as recently re-
corded in a paper by L. Y. Schermerhorn before the Engineers' Club of Philadelphia,
the water-jet method has been similarly employed in many different places by different
persons. In the United States, in the improvement of the Mississippi and Missouri riv-
ers, large numbers of piles have been driven for the construction of the brush and pile
dikes, and in the sinking of these piles the water jet has been in use since 1881. A
great variety of experiments were undertaken upon this work to establish the best de-
tails for the use of the jet. This experience demonstrated certain fundamental princi-
ples as contributing essentially to the best results, prominent among which were the fol-
lowing: That the water jet cannot be relied upon to give satisfactory results in mate-
rial containing a large percentage of gravel ; that it should be capable of such concen-
tration of its force as will permit the stream to be delivered through a nozzle not more
than 1£ inches in diameter, and frequently somewhat less, and with pump power capa-
ble of giving a nozzle-pressure of from 75 to 150 pounds per square inch; that in sand
free from gravel the best results are obtained with the larger nozzle and reduced pres-
sure, w T hile the presence of gravel required the smaller nozzle and higher pressure.—
Cassier's Magazine.