Page images
PDF
EPUB
[graphic][merged small]

harm, or more, than the crawfish. Both these pests attack the levee from the river side, boring into the earth, straight through, perhaps, or maybe tortuously. These holes spurt water when the river reaches the level of their openings, and if allowed to flow unchecked, will increase in size until they undermine the entire embankment, and a crevasse results.

They are fought in the same manner. If discovered before high water, the holes are repaired then. If they are not discovered until the flood is on, a box is built out into the river in front of the levee, the embankment forming the inner side. This box is filled with dirt sacks. This stops the leak, but it is expensive, since the box must be large enough to be sure to enclose the intake, which naturally cannot be seen or found beneath the water.

Seepage is one of the first troubles encountered when the river begins to rise. Through the forty, sixty or hundred foot base, the water will seep, and

up from beneath as well. Ditches are the remedy for this. Some seepage seems inevitable. Unless it becomes so heavy that it collects behind the levee and threatens to soften it, it does not mean much. If the seepage becomes serious, "blanketing" is resorted to. The "blanket" is of dirt, spread over the face of the levee, plastering it thick with mud which works its way into the crevices which are leaking.

Day and night the levees are guarded, when the river threatens thus, militiamen and volunteers do turn about with Winchesters and shotguns, watching for any sign of trouble. There is another reason for the guards. A break on one side of the river relieves the danger for miles on the other side above and below. To save his own broad acres, temptation to use a little dynamite across the river might be too strong for some weak brother. So the rifles mean business, and when one visits a levee in flood time, it is with adequate explanation of one's

reasons.

TO SAVE SHIPS FROM ICEBERGS

A

By

C. LINTERN SIBLEY

[blocks in formation]

never once failing to record the presence of ice.

The instrument is really an adaptation of the electrical resistance thermometer. It is permanently attached to the prow of the vessel, and is connected by electrical wires to a dial in the chart room, where every slight variation in the temperature of the water may now be recorded. Professor Barnes says that at present navigators rely almost entirely on the lookout to detect the presence of ice, and the danger of this practice has been emphasized by the Titanic disaster.

[graphic]

PROF. HOWARD T. BARNES, INVENTOR OF
THE ICEBERG DETECTOR FOR USE
OF SHIPS AT SEA.

tion of the Titanic is now declared to be impossible, provided a recently invented instrument be installed, and its indicator faithfully observed on all ocean lines. Professor Howard T. Barnes, D. Sc., F. R. C. S., director of the physical laboratories at McGill University, Montreal, is the inventor of this instrument, which is attracting much attention among scientific men both on this continent and in Great Britain. He calls his invention the micro-thermometer. It is, in reality, a super-sensitive thermometer which, it is claimed, will infallibly detect an iceberg at a distance of two miles on the windward side, and seven miles on the leeward side. Professor Barnes has conducted numerous experiments with the instrument on the Canadian government vessels in the river and gulf of the St. Lawrence, and these have in every way borne out his claims. In May of this year, when on his way to England, to lecture on his invention, by invitation, before the Royal Institute, he conducted experiments on the Canadian Northern liner, Royal George, sailing from Halifax to Liverpool. This was soon after the Titanic disaster, when ice was still plentiful along the steamship tracks on the Atlantic, and again the instrument fully established the assertions of its inventor,

"A show is also made," he said, "of taking the temperature of the water, but the method of doing this is so crude that little reliance is placed upon it by navigators. Captain Lecky, in his 'Wrinkles on Navigation,' shows this conclusively. The method now in use is to pull a bucket of water up over the side of the vessel, and to dip a mercury or alcohol thermometer in it to get a record of the temperature. It is just an ordinary house thermometer that is used. It is a haphazard and unscientific method of taking observations of sea temperaturefirst, because records are only obtained at more or less long intervals; second, because it is impossible by this means to detect small variations, while variations of half a degree, or even a whole degree, are apt to go unnoticed.

"Now the micro-thermometer is so sensitive that it will record a variation of

[blocks in formation]

AN ACTUAL RECORD MADE BY PROFESSOR BARNES' MICRO-THERMOMETER ON BOARD SHIF WHEN PASSING AN ICEBERG.

one-thousandth of a degree, and so striking is its record that whereas on an ordinary thermometer a single degree is usually represented by only one-eighth of an inch, the micro-thermometer represents a single degree by an interval of two feet.

"Moreover, the micro-thermometer is designed, not to be dipped into buckets of water at frequent intervals, but to be permanently attached to the ship under the water line, and, by means of wires leading from it to the chart room, to make a continuous record in the chart room of the water temperature. With this thermometer being towed along with the ship, and with a continuously-recording instrument attached to it in the chart room, the presence of an iceberg unerringly makes itself known by the persistence of a gradient of temperature.

"Here is how I would equip a ship. An iceberg, of course, is continuously giving off a current of cold water all around it. This cold water, being fresh

water, is lighter than the salt water, and spreads out over the surface of the sea for two miles on the windward side, and seven miles on the leeward side. Now if a micro-thermometer were fitted at the bow, about two feet below the water line, and another micro-thermometer at the stern, as deep down as the draught of the ship would allow, the bow thermometer would catch the cold surface current, while the stern thermometer would remain at the normal sea temperature. In this way whenever the differential record read so that the bow thermometer was colder than the deep stern instrument, this would be taken as an indication of disturbance due to the presence of icean unmistakable indication, because it could be due to no other cause. If the recording instrument showed this temperature to persist and become greater, the ship would be approaching the ice; if it decreased the ship would be leaving the ice behind."

The invention of this thermometer is the outcome of many years of research work, and it arose from the need of a better instrument to assist him in his study of calorimetry. It was he who developed the continuous flow method of calorimetry-a great advance both for simplicity and accuracy on the older methods. Subsequent to this development, his researches on the specific heat of water became a classic, and, after occupying the attention of the Royal Society of London, England, in special session, were made the basis of a report on the subject to the conference of physicists at the Paris Exhibition.

Professor Barnes has for years been looked upon as one of the world's greatest authorities upon ice, and for his researches has rerecogni"Ice Forwas the

in ice formation he ceived widespread tion. His book on mation and Frazil" first authoritative

work on the subject. It attracted such attention among scientific men that he was invited to read a paper upon his researches before the British Association, at its annual meeting held in Leicester, England, in September, 1907. The paper he presented on that occasion, entitled "The Ice Problem in Engineering Work in Canada," demonstrated the feasibility of coping with a situation which up till then had been regarded as involving inevitable interruptions to the continuous operation of water power plants in Canada during the severe winters to which that country is liable.

He had great difficulty in making people believe that he had achieved the seemingly impossible task of making water powers continuous despite long periods of zero weather. the injection of water upon its power plants, ulous, but at

His method, heat under entrance into seemed ridiclast Mr.

[graphic]

THIS PHOTOGRAPH, TAKEN IN PROFESSOR BARNES' LABORATORY IN MONTREAL SHOWS (A) THE MICRO-THERMOMETER BEING TESTED IN A VESSEL OF WATER, AND

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][graphic][merged small][merged small][merged small][merged small][merged small]

Sayings of Diogenes Laertius

¶ Fortune is unstable, while our will is free.

¶ It takes a wise man to discover a wise man.

¶ Xenophanes was the first person who asserted that the soul is a spirit.

The chief good is the suspension of the judgment, which tranquillity of mind follows like its shadow.

« PreviousContinue »