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Senate of the United States, on the subject of steam boiler er
JANUARY 8, 1849.~Read, and referred to the Committee on Patents and the Patent Office.
for the use of the Senate, referred to the Committee on Printing.
discharged from so much of the report of the Commissioner of Patents as relates to
Committee on Commerce.
number be printed for the use of the Senate.
UNITED STATES PATENT OFFICE,
December 30, 1848. Sır: In compliance with the resolution of the Senate, adopted January 24, 1848, in the following words, viz: "Resolved, That the Commissioner of Patents be directed to report to the Senate such information as he may have in his possession, or may obtain, that he deems important, with reference to further legislation by Congress for the prevention of the explosion of steam boilers, used in boats or for engines on railroads, and whether any amendments to the patent laws are advisable in effecting such object," I have the honor respectfully to report:
The resolution of the Senate embraces two calls: first, for information deemed important with reference to the prevention of boiler explosions; and, second, for the opinion of the undersigned as to whether "any amendments to the patent laws are deemed advisable in effecting such object." With regard to the second point of inquiry, the undersigned has no hesitation in expressing his belief that no modifications of the patent laws would have any tendency to lessen the evils which it is the object of the proposed legislation to mitigate.
In order to comply as fully as possible with the requirements of the resolution, a circular was issued by this office on the 7th of March, 1848, (a copy of which is hereto appended, marked A,) addresses to the collectors of every port in the United States. Replies were received from sixty-eight collectors, as well as numerous communications from other sources, with reference to the subject of explosions. An abstract of the replies of collectors will
475 tleh p. Rek
be found appended, (marked B.) The returns are evidently.incomplete, as to the number of boats which have been destroyed by the explosion of their boilers during the period stated in the inquiries, and meagre in the details of those accidents, accounts of which are furnished; yet sufficient, perhaps, is stated from which to form a tolerably correct opinion as to the amount of the evil, the causes on which it depends, and the remedies which legislation is competent to apply to it. Such of the results of these inquiries as could be presented in tabular form will be found in the appendix, (marked C.) The returns of explosions on railroads are so few and unsatisfactory that they have not been taken into considera. tion in this report. All the information which the office has received in regard to these is given in the table in the appendix, (marked D.)
The returns received enumerate two hundred and thirty-three explosions of steamboat boilers, from which accidents the number killed (as given in one hundred and sixty-four cases) is eighteen hundred and five; making an average of eleven for each accident. If the sixty-nine cases in which the number killed is not stated average the same, the total loss of life, in the two hundred and thirty-three cases, would amount to two thousand five hundred and sixty-three.
The number wounded, in one hundred and eleven cases, is one thousand and fifteen-an average of nine. The same calculation as in the former case would give as the total number wounded, two thousand and ninety-seven; making the whole number of sufferers, four thousand six hundred and sixty.
The amount of pecuniary loss sustained in seventy-five cases is nine hundred and ninety-seven thousand six hundred and fifty dolJars-giving an average loss of thirteen thousand three hundred and two dollars by each explosion; which, applied to the whole number of cases, would make the entire loss three millions ninety-nine thousand three hundred and sixty-six dollars.
Of the explosions enumerated, two hundred and two, or .867 per cent., occurred on the southern and western waters; one hundred and forty-six, or .626 per cent. on the Mississippi river and its tributaries; ninety, or .386 per cent., on the Mississippi alone; forty, or .172 per cent. on the Ohio. The number of explosions for each locality, is given in detail, in the appendix (E.]
From 1830 to the present time the number of explosions given is 198; making an average of ten each year, with 110 as the average annual loss of life, and ninety the annual average of wounded; the total number of sufferers, annually, being two hundred; and the annual pecuniary loss one hundred and thirty-three thousand and twenty dollars.
The steamboat tonnage of the western rivers in 1846, was 249,055; and the whole value of the commerce of these boats $62,206,719. The probable extent in miles of the steam navigation of the western waters, as estimated by Colonel Long, of the topographical engineers, is sixteen thousand six hundred and seventy four.*
* American almanac, 1849.
The whole number of steam vessels built in the United States from 1830 to 1847, inclusive, is nineteen hundred and fifteen.* The losses by explosion during the same period amount, according to the returns furnished, to one hundred and ninety-eight, or about ten per cent.
There is something in the appalling nature of steam boiler explosions which strikes, public attention, and has given rise to an impression that steamboats and railroads are more dangerous modes of conveyance than any others. It is to be regretted that no direct means of making a comparison through a series of years, between the losses by ordinary navigation, and those by steam navigation, are in the possession of the office.
To make a comparison which should be perfectly fair, it would be necessary to take an equal number of steamers and other vessels having the same route, and exposed in common to the same sources of danger, except those arising from the employment of steam as the motive power. It would be very difficult to obtain the means of doing this. But a general and somewhat loose comparison can be made, which may serve to correct a false impression which undeniably exists with regard to the comparative safety of the two modes of travel. It appears from a statement contained in a memmorial addressed to Congress on this subject, that in the year 1839 the number of American vessels lost by ordinary navigation was one thousand and fifty-nine, and that in the month of December alone, of that year, one hundred and eighty-one vessels, and one hundred and seventy-nine lives were destroyed. + Thus the number of lives lost in that month is nearly double the average annual loss of life by steamboat explosions, as deduced from the foregoing calculations. A comparison of the number of vessels exposed would not give a fair estimate of the relative danger of the two modes of transportation, because the number of individuals exposed to the dangers from steam transportation is vastly greater in proportion to the number of vessels than those exposed in ordinary navigation.
In speaking thus favorably of the comparative safety of steam navigation, it is not intended to assert that steam has not added, in each individual case, a new element of danger to the means of transportation where it is employed. But in endeavoring to estimate the absolute risk - in each kind of navigation we must take into the account every source of danger to which each is subject, and so doing, we find the risk from ordinary navigation to exceed that from navigation by steam. In the case of the former, disasters frequently occur in a distant quarter, in the presence of comparatively sew witnesses, and many of them are never noticed by the press. They are regarded as matters of course, the results of natural causes, over which man has no control. In the latter, on the contrary, every circumstance is present which would tend to exaggerate the impression upon the public mind. It is merely for
Rep. Sec. Treas. Dec 1847. Sen. Doc. No. 5., 30th Cong., 1st sess., p. 396. † Sen. Doc. 309, 1st session 26th Congress.
purpose of removing an injurious misconception that the comparison just given, which does not pretend to accuracy, has been made.
For the five years ending with 1828, the ratio of explosions to the number of exposures on steamboat routes from New York city, was one to one hundred and twenty-six thousand two hundred and eleven. In the next five years, ending with 1833, the ratio was reduced so as to show one to one hundred and fifty one thousand nine hundred and thirty-one; and in the next five years it fell to one to one million nine hundred and eighty-five thousand seven hundred and eighty-seven.
The result of a similar calculation with reference to western navigation is less favorable. In the memorial of a committee on abuses of steam navigation, at Cincinnati, laid before Congress at its last session, the number of lives annually exposed to the dangers of steam navigation is estimated at eight million one hundred and eighty-five thousand. Taking the average annual loss of life on these waters at seventy, t we find its ratio to the whole number of lives exposed, to be one to one hundred and two thousand six hundred and forty-two, and the ratio of explosions to the number of exposures to be one to five hundred and sixty thousand six hundred and sixteen.
From these facts it appears that the dangers of steam navigation on the western waters, though obviously greater than those at the east, still bear a favorable comparison with those of other modes of water conveyance. Yet so much terror has been excited in the public mind, by accidents of this kind, that the prevention of them has (and no doubt properly) been considered by those nations which have made most use of the powerful and useful, though dangerous agency of steam, as calling for special legislative interference.. As early as 1817,5 a committee of the British Parliament was charged with the investigation of the causes of explosions, and much valuable information was elicited by the examination of engineers and others, which they instituted That committee felt and acknowledged the inexpediency of "egislative interference with the management of private concerns or property, further than the public safety should demand," but they urged that a consideration of what is due to public safety has on several occasions, established the principle that where that safety may be endangered by ignorance, avarice, or inattention, against which individuals are unable, either from the want of knowledge or of the power, to protect themselves, it becomes the duty of parliament to interfere." This principle has been acknowledged also, by the French government and by our own. Of the propriety and necessity for legislation of some kind there can be no doubt; the only question is, as to what the character of that legislation ought to be. The determination of this question involves the consideration of the causes of these fatal occurrences, and the remedies which have been proposed.
*Redfield's replies to British Commissioners, Sen. Doc. 309, 1st session 26th Congress.
The fact that the steam engine has come into such general use, and has been placed under the management of men widely differing in their education, and judgment, and many of them entirely destitute of scientific knowledge, has given rise to a great variety of hypotheses designed to account for the explosions of steam boilers. Most of them have been mere crude speculations, without any foundation in fact or. in physical analogy. Such are the pretended explanations which refer the explosion to the presence of electricity or the generation of hydrogen gas, and its union in explosive proportion with oxygen within the boiler. Of the former hypothesis, it is only necessary to say that electricity, if present at all, would reside on the outside of the boiler; and of the latter, that the necessary conditions are not present which would render it probable. In the ordinary condition of a boiler, no hydrogen is produced; and if it were present, it could not procure a sufficient supply of oxygen to combine with it in explosive proportion.*
Another hypothesis accounts for the explosion in this way: the water falling below the fire line in the boiler, the portion of the latter thus exposed, becomes excessively heated, and communicates its heat to the steam, which thus becomes surcharged with heat. Now steam, when heated separately from the water which generates it, follows the law which regulates the expansion of ordinary gases, i. e., it expands is part of its bulk (or nearly) for every degreee of Fahrenheit above the freezing point. The increase of elastic force is therefore, under these circumstances, very small in proportion to the increase of temperature. But while the steam is thus surcharged, a supply of water is sent into the boiler, the surcharged steam at once becomes converted into saturated steam of high elastic power, and an explosion follows. This hypothesis, although ingenious, and long received as the true explanation of the phenomenon, is found to be contradicted by the results of careful and repeated experiments. The committee of the Franklin Institute, t "appointed to examine into the causes of the explosions of the boilers used on board of steamboats, and to devise the most effectual means of preventing the accidents, or of diminishing the extent of their injurious effects,'' to whose valuable labors, which have thrown great light upon this whole subject, frequent reference will be made in this report, made a series of experiments in the prosecution of one point of their enquiries, to ascertain whether
The production of hydrogen was referred to the decomposition of the water by the heated metal. The conclusions drawn by the Franklin Institute committee, from their experiments, to determine "whether any permanently elastic fluids are produced within a boiler, when the metal becomes intensely heated," are."1. That the gas obtained by injecting water upon the bottom of a boiler which was at a bright red heat, was nitrogen gas with variable quantity of oxygen; it was in fact atmospheric air, deprived by the heated metal of more or less of its oxygen. 2. That this air was derived principally from the current into the boiler when surcharged steam had ceased to be formed, and the boiler was left dry; there will therefore be no such quantity in a working boiler where the air must be supplied from the cold water thrown in. 3. That water in contact with heated iron in a steam boiler, the surface being in its ordinary state, clean, not bright, is not decomposed by heat."--Frank. Journ. vol. xvii, p. 222.
† Dr. A. D. Bache was the chairman of this committee.