CHIEF CRONIN REPLIES TO “CRUSADER.”
LIKE Banquo’s Ghost, “Crusader” will not down, but continues to haunt the readers of THE JOURNAL and myself with his oft repeated tale. He is evidently of the opinion that a good thing can’t be told too often, and as he is satisfied that his hobby is the best in the world, he rides him on every possible occasion. I don’t blame him. It is human nature. But I must not let his chaff pass for grain. He says that I am not “ progressive.” For reply I refer to my Department, with the consciousness that it is equipped with the very best of mechanical appliances, including Oyston’s and other spray nozzles, as fast as their efficiency is demonstrated, and if I do not adopt “Crusader’s” scientific theories it is for the simple reason that he has as yet failed to convince either my brother Fireengineers or myself that they are correct. “ Crusader ’’ still either misapprehends or misquotes me I say again, as I have said before, that, for a certain class of fires, small ones or those confined to rooms, spray nozzles may be used with propriety and success, but that for large, fierce fires they are useless. They cannot and will not penetrate to the base, and consequently will not cover as much real fire surface as a solid stream, which will penetrate to the base. As far as his mathematical calculations aJe concerned, we all know that a street fountain with a spray nozzle will cover a larger area in the air than a solid nozzle, but we also know that its power is spent in the distribution, and that it will not throw one-third as high or as far with the same pressure as the solid nozzle. So with firo nozzles, and I insist that we must penetrate to the source or base to extinguish large fires. I have tried a pressure of 150 pounds to the square inch on a spray nozzle, and under favorable conditions the distance thrown was from 50 to 62 feet. With a 1 3/8 inch nozzle under the same pressure and at the same time, I have thrown from 160 to 180 feet Against a strong wind the spray only threw from 15 to ao feet, while the solid stream was thrown from 50 to 65 feet. It will be. readily seen from the above which stream would cover the most surface had it to wet down or extinguish the fire on the roof or sides of buildings from 40 to 70 feet high or from 80 to 100 feet in depth. In cases of this kind it is evident that the spray nozzle could not reach the roof and but a short space on the sides, and consequently could cover none of the actual fire surface, whereas the solid stream, if sufficiently large, could and would. Numerous examples can be cited where the spray nozzle, from the very nature of things, could not cover at its base or source an inch of actual fire surface.
He objects to my quoting the report in the Boston paper, which he terms sensational and unworthy to be introduced in a scientific discussion. I quoted the report of an absolute practical fact which came under the notice of close and trustworthy observers, and let me say that the basis of all knowledge on this subject lies in observed facts or practical knowledge reduced to a system. He quotes me, “Mr. Cronin says he only claims large solid streams in large fierce fires,” and continues, “does he intend to wait while the fires become large, for he has said nothing about fighting fires before they become large. Now my place is to prevent fires from becoming large, and to dispense with the use of large solid streams as much as possible for the very reason that we cannot utilize but a small percentage of water with a solid stream either at short or long ranges.” “ Crusader ” bogs the question when he talks of preventing large fires. In all cities in this country of any size, with their cheap, dangerous, and illy-constructed buildings, it often occurs that before the fire is discovered it is a large one, on which the spray nozzle would be of no more avail than the old bucket system. These arc the fires upon which solid streams, and the larger the better, must be used, and they are the class of fires to which 1 have always referred. In regard to utilizing water : In fires of this class, that is large ones, whenever a solid or any other kind of stream can be got to its source all the water is utilized, and the fire must go out if a sufficient quantity be thrown upon it in time. Criticizing my knowledge of “ latent heat,” “Crusader” says I do not know how to use it, and quotes, “This example it must be understood has only reference to the quantity of heat conveyed to water in boilers or other suitable vessels.” He adds, “ now the substance of this is that there is no steam formed. If the reader will turn to page 337, March 30, 1878, he will find that Mr. Cronin says, when speaking on this subject, ‘and steam generated in such quantities that rising in mighty clouds it must absorb and conquer its antagonist.’ Now this is a Hat contradiction of his last statement. Which shall we believe ? They •are neither of them true, so we must believe neither.” On the contrary both are true. In my last I gave an example of the conversion of water into vapor, and concluded it with the sentence first above quoted, referring to which “ Crusader” says, “ the substance of this is, that there is no steam formed.” If vapor don’t mean steam, and steam don’t mean vapor, he is right, but if the terms are synonontsus then he is wrong in his deductions.
Continuing, he contradicts my statement of March 30, 1878, that steam absorbs heat, and by the term steam I mean “aqueous vapor,” which does absorb heat by overcoming the molecular forces and abolishing the attraction of the atoms which compose the molecules of steam or vapor, separat ing them into their original free elements, which is the case if the heat is sufficiently intense. What the result of this separation is, I have already stated in my communication of March 30, 1878. It also acts by retarding the ascending heat currents, thereby preventing an increased supply of air to the fire, which would be the case were it not for its (steam) absorbing qualities, if it be generated in sufficient quantities to pass through the fire. It also acts by its elastic force, for in expanding space has to be occupied and the air is pushed away in all directions. To do this requires the performance of work, which is done at the expense of the heat with which the steam is in contact. For the quantity of that absorption I refer him to the leading equations of the mechanical theory of heat, which will tell him how to calculate the quantity of heat which disappears through a given change of volume of bodies, including those of a completely gaseous form, whether under increased or diminished pressure. In fine, “ Crusader” vainly seeks with his spray nozzle to anticipate the certain action of the heat, by mechanically dividing the water, before it is put in contact with the fir;, instead of permitting the heat to do so, not aware that by his proposition he loses immensely for practical purposes the very power he seeks to utilize. In the heating and cooling of a body three different effects must be considered. First, the change of temperature. Second, the external mechanical labor which results in the variation of the volume of bodies, and the resultant pressures on their surfaces. Third, the internal labor, which means the change of aggregation. The definite relations between these effects and the heat lost and gained by the body, with the discovery of the quantity of these relations is regarded as one of the greatest advances made in modern physics. The experiments, until very recently, have had for their principal object the relations of heat and of external labor, from which the numerical data now in use was deduced, but late experiments in relation to internal labor, though rare and attended with many perplexities, have been successfully made.
How to extinguish the “crockery store” fire is given at last, and while “ Crusader” is careful to divide his nozzle into infinitessimal sprays, and state the exact pressure (150 pounds) which he would use, he is equally careful to forget to give the size of the building, temperature and quantity of heat, condition of the atmosphere and other data which I consider of the greatest importance, but which he loses sight of in the steam created by his spray circle ten feet in diameter. If the fire be of sufficient intensity his stream would be more apt to pass into the atmosphere than to extinguish the fire, for even with an average solid nozzle in intense fires the stream will be converted into vapor long before it reaches the service of the fire, and consequently lose some of its power, as was the case with the streams at the Boston fire previously quoted. As to Chief Green, of Boston, he extinguished the great fire referred to without the use of sprays, and would, I am sure, do so again if the occasion should unfortunately occur. “Crusader’s” reference to the New York Department of a year or two ago, as one having only “ primitive appliances ” is an uncalled for reflection upon an organization which embraces in its personal and equipment all the best elements of the manhood, mechanism and system as yet introduced, and stamp him as either wilfully prejudiced or culpably ignorant of the true state of affairs.