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with the danger of falling walls added, a more dreadful catastrophe can hardly be imagined.
With the usual form of boiler . construction this is almost unavoidable. The crownsheet is usually supported from the roof of the boiler by a large number of iron rods called “stay bolts," riveted on the inside of the firebox where their heads are constantly subjected to the most intense heat. When red heat is attained in the crownsheet through lack of water, the heads of the stay bolts are the first parts to be affected, and under pressure from within, pull through
THE FIREBOX OF AN ORDINARY BOILER AFTER EXPLOSION FROM LACK and leave the sheets un
The crownsbeet has been torn away, leaving the stay bolts. supported and at the mercy of the terrific stored energy.
by vertical plates running in retreat from As far as the external appearance is the fire. The plates are perforated with concerned the Jacobs-Shupert firebox large holes to permit the free circulation does not differ greatly from others, the of water and steam. unique features being within the boiler I t is hardly necessary to state that this itself. One need only to glance at the construction will withstand much more photographs of the partly constructed overheating than the common type of firebox to realize the immensely superior boiler. strength it possesses over the old type. What we are all most interested to The top and sides instead of being made know is whether our lives will be safer of single sheets as in the old design are on a train behind an engine equipped constructed in U shaped sections a few with such a boiler, and so a brief descripinches in width, formed to the arch of tion of the test to which it was recently the box, riveted together and reinforced subjected may be of interest.
On September 26th last, in the presence of many engineers from various cities and two representatives of the Interstate Commerce Commission, the above mentioned railway officials subjected a boiler equipped with a firebox of this design to a low-water test. This boiler was taken from one of the company's highest grade locomotives and set up in a large vacant tract of land in the neighborhood of their shops. The firebox was equipped to burn oil. The boiler was fitted with two steam gauges, one to verify the other, and two water glasses, one to show the height of the water above the crownsheet, the other, the distance it might fall below during the test.
A pump was also set up at a distance to FIREBOX PARTLY CONSTRUCTED, SHOWING SECTIONS AND REINFORCING PLATES.
supply water during the experiment.
under the intense heat applied during the test.
The pressure gauges, height of water, and records of temperature were observed by an engineer in a steel firebox chained to a flat car a short distance from the boiler. The remainder of the audience witnessed the proceedings through a telescope from a safe distance.
Statistics of the test are of little interest, but the trial is the most severe that has ever been given any boiler and one which the common type could not have withstood. It further demonstrates that a boiler so equipped could not, under
the common conditions which cause exfallen about five inches below the crown- plosions, create a disaster such as we so sheet and a temperature of 1,125 degrees often read of in the daily papers. Bein the firebox was recorded by a pyro- cause of the reinforcement of the firebox, meter. In other words, the crownsheet little or no damage could result even if had attained a good working heat. At a blowout should take place in one of this point the fire was shut off and cold the sections, as it would be so small as water turned in the boiler until the steam to amount practically to the opening of a pressure was somewhat reduced. In spite valve for the relief of the unusual presof this terrific treatment, and the fact sure. that at the time the crownsheet was red It is greatly to be hoped, if this form hot, the boiler withheld a pressure of 230 of boiler construction solves the explopounds to the square inch, and showed sion problem, that it may be adopted no ill effects further than a few trifling throughout the world, wherever boilers leaks due to expansion of the plates are in use.
D AMMING THE MISSISSIPPI
F. G. MOORHEAD
OT far from the spot where a thousand men are working, beaver like,
Jim Bludsoe ran the Prairie to throw across the mighty river a strucBelle aground and "held her ture of cement and stone which shall nozzle agin the bank till the hold the rushing waters in check and
last galoot was ashore," a subserviently render up to its master mile-wide dam is being built which will 250,000 horse-power with which to run completely change the contour and the factories, mills, and workshops of the topography of the Mississippi River and very heart of the grain belt. Already, on the historic land thereabouts. Incidentally both sides of the Mississippi, the dam a steamboat canal, nine miles long, built has begun to assume shape. Two gangs forty years ago at a cost of $8,000,000, of men are throwing out abutments and is to be completely drowned out, with creeping toward each other across a not a stick or a stone left to show where watery path. Twenty million dollars will it once made possible the passage of the be spent before the two gangs meet, but treacherous Des Moines rapids.
the investment is considered a good one The sons of the men who damned the by some of the shrewdest financiers of Mississippi a generation ago are now the country. busily engaged in damming it. The work F or over sixty years Keokuk has will occupy two years more, but already dreamed of harnessing the turbulent
BUNK HOUSES OF THE WORKMEN ON THE IOWA SHORE.
bottom drops twenty-four feet to the navigable depths of the open river below Keokuk. At an annual cost of $50,000
the government has maintained this canal waters of the Mississippi and making the for forty years. Within the next two Des Moines rapids do the work of man. years it will have disappeared under As long ago as 1848 the Mississippi twenty feet of water, part of the bed of River Improvement Association was a new inland lake forty miles long and formed, with a capital of $1,000,000, its from one to five miles wide. For the objects being to improve navigation and dream of two-thirds of a century is being harness the water power that might be realized at last. Five years ago, after developed in the process. The Civil War numberless disheartening failures, a bill passed and still the project remained a was passed through Congress granting dream. The United States government a franchise and the first glimmerings of went a long ways toward shattering the a realized dream began to appear. dream for all time by building a nine- It was no small task to get both houses mile canal alongside of the perilous of Congress to agree on a franchise rapids where many a steamboat and which establishes the precedent of buildmany a raft had met demolition, estab- ing a dam entirely across the country's lishing three locks for the purpose of largest river. But the Keokuk boosters raising and lowering craft from one level were shrewd. They introduced old river to another. Flowing through the high, pilots and captains before the committees limestone gorges on either side, step by to testify that the dam would improve step the solid lime rock of the river's navigation rather than hinder it; they
enlisted the co-operation of the army Mr. Hugh L. Cooper, the engineer in engineers and voluntarily agreed to re- charge, has given Keokuk assurances place the canal and its three locks with a that the work can be completed in thirty single lock, which would answer every months. The first year has been one of purpose, and the twenty-year old dry preparation mainly, but the end of 1911 dock with a new one, and from now to will find the dam well under way, exthe end of time to supply the power to tending out from both the Iowa and the operate the new lock and the new dry Illinois shores, and the power house dock, absolutely free of charge. On practically completed. January 27, 1905, the lower house passed The project gives to the Mississippi the bill granting the desired franchise. Valley the largest water-power developOn February 2, it passed the Senate and ment in the entire country, with the on February 9, 1905, President Roosevelt single exception of the combined plants signed the bill.
at Niagara Falls, and the largest dam in Immediately there began the hunt for the world, with the single exception of capital. The bill required that the work the Assouan dam across the Nile in begin within five years and be completed Egypt. There will be required in the within ten. It was not until a month or construction 500,000 cubic yards of two before the five-year limit had ex- masonry, 500,000 barrels of cement, and pired that work actually began. Even 7,000 tons of steel. then the doubters remained, crying that The dam, including abutments, will be the limestone cliffs were being uncov 4,700 feet long. It will extend from a ered simply to keep the franchise and point a little north of the center of the that the dam would never be built. But town of Hamilton, Illinois, due westas the weeks passed and the gangs of ward across the river to a point near workmen grew, from a few score to sev- the Iowa shore, under the bluffs at eral hundred, and the approaches to the Keokuk, where the power house, 1,400 dam on the Illinois shore gradually feet long, will link shore with shore. The began to show, the scoffers fled and all mammoth dam will be of solid concrete, Keokuk joined in such a jubilation as thirty-five feet wide on the bottom and the old Mississippi Valley has not known about thirty feet high. The upper stream since the palmy days of steamboat racing. face will be vertical with a rounded top On January 8, 1910, definite announce- eight feet wide, the lower side ending in ment was made that the dam would be a curve connecting with the bottom, so built. By the first of February several that the water coming over will not fall, score of men were at work. The con- but slide down the face and be given a struction was continued uninterrupted horizontal direction at the bottom of the from that time, and early in December, river. The whole height is thirty-seven 1910, five hundred men started to work feet, the dam being locked into the rock on the Iowa shore.
bottom seven feet deep, to prevent any