Popular Science Monthly/Volume 15/September 1879/Correspondence
WILL you permit a brief criticism of your selections for "The Popular Science Monthly"? My appreciation of the journal is sufficiently indicated in its reception and careful reading from the time it was begun. I have for some fifty years tried to do my own thinking—not so self-sufficiently, however, that I am not very glad to get what true help I can from other thinkers.
I have been attracted to "The Popular Science Monthly" by the evident desire and purpose of its conductors to give a fair hearing to all views, pro or con, on any subject of general scientific interest. There is one, however, now before the world which, in importance to the whole human family, can be assigned to no second place, which, in my view, you treat in a very partisan manner. I refer to the Harmonial Philosophy, Spiritualism, or whatever it may be called. This question, whether evolving truths of the deepest importance to humanity, or a species of insanity, delusion, or imposition, demands attention and discussion; for millions of people are to-day affected more or less by its phenomena and teachings, and it is spreading with a rapidity un-realized by the indifferent observer. From its first opening with the Fox girls near Rochester, New York, to the present, I have observed it closely, and often under very favorable circumstances. To endorse it en masse would to me be folly; to utterly ignore it, equally so.
I am fully satisfied that there are great and most important truths involved in the subject, which demand elimination from what may be accompanying rubbish. Now, when you select for "The Popular Science Monthly" articles all, or nearly so, on one side of this question, and from men like Hammond, Beard, Gairdner, Trowbridge, etc., you leave the path of true science for that of the partisan.
To me, as well as several other readers of the journal with whom I have communicated, a fair discussion of this subject would not only add interest, but remove a present offense. You might lose some bigoted and fossilized readers, but you would gain an equal if not larger number of the less prejudiced.
|A. L. Child, M.D.|
|Plattsmouth, Nebraska, May 30, 1879.|
In an article on "Wasted Forces" by William H. Wahl, Ph.D., in "The Popular Science Monthly" for July, 1879, I note some remarkable statements in that part of the article which deals with the efficiency of steam-engines. The writer seems to have ignored the principal cause of wasted heat in the steam-engine, viz., the efficiency of the fluid, and to have augmented the other losses in order, apparently, to account for the low efficiency of the whole machine. In doing this he has given figures, which not only leave wrong impressions in the minds of those not familiar with the subject, but he makes opportunities for improvement seem far greater in some directions than they are. I do not care to call in question the fifteen per cent, which Mr. Wahl gives as the greatest efficiency yet obtained from steam-engines, but in locomotive-engines, with which I am most familiar, five per cent, will more nearly represent the efficiency of average performance. Granting that fifteen per cent, may be obtained in the most economical engines, it is to Mr. Wahl's method of accounting for the loss of eighty-five per cent, that I object. On page 292 one reads: "For by far the greater portion of this eighty-five per cent, of wasted power is chargeable directly to the steam-boiler, and but a comparatively small proportion thereof to the engine." And again, on page 293: "Summing up all the items of loss in the steam-generator, it is probable that with the best forms of boiler which it has been possible to construct, not more than twenty-five per cent, of the theoretical thermal effect of the fuel is utilized in the generation of steam; and of this twenty-five per cent., from five to ten per cent, is lost somewhere on the passage of the steam from the boiler to and through the engine by condensation in steam-pipes, and friction of the machinery, leaving us but fifteen or twenty per cent, actually realized in practice." As a matter of fact I have repeatedly observed from fifty to fifty-five per cent, of the total theoretical number of heat-units obtainable from the complete combustion of bituminous coal transferred to the water and steam in the boiler from locomotive fire-boxes, in which the proper burning of coal is far more difficult than in stationary fire-boxes, or those with natural draught and ample room; in such fire-boxes as last mentioned, coal is burned so as to transfer from seventy to seventy-five per cent, of its theoretical heat to the boiler, and I do not know that this is the best attainable. Mr. Wahl's limit of twenty-five per cent, efficiency of fire-box, or, as he well terms the boiler and fire-box, the "steam-generator," is therefore entirely too low; neither has he mentioned the principal cause of the loss of heat in steam-engines, viz., the low efficiency of steam as a medium on account of its high latent heat, a very small part of which, at best, can be utilized even in condensing engines, and still less in non-condensing engines. In locomotive-engines the following statement will represent a fair average performance, with corresponding approximate rates of loss from different causes:
|Efficiency of steam-generator||55||per ct.|
|Efficiency of steam and steam-engine.||8||"|
|Efficiency of machine .55 x .8 =||4.4||"|
The low efficiency of the steam stands somewhat as follows:
|Units of heat required to convert one pound of water from 60° Fahr. to steam at 125 pounds 1 pressure||1,160|
|Of which the latent heat is||865|
which can not be converted into work in the locomotive-engine: neither is the difference 1,160 865 295 all available; for 212 60 152 of this was required to heat the pound of water to the boiling-point at atmospheric pressure, and still more at one hundred and twenty-five pounds' pressure. This reduces to 295—152=143 units, all of which is not obtained from each 1,160 units expended, for the steam is exhausted at some pressure above atmosphere to get more work from the engine and to blow the fire, so that we really get but about ninety useful units out of 1,160 expended, or about eight per cent. In best stationary engines (which are to yield fifteen per cent, efficiency) this would stand:
|Efficiency of generator, approx.||75||per cent.|
|Efficiency of steam and engine "||20||"|
|Efficiency of whole machine, .75. 20||15||"|
The twenty per cent, here in place of the eight per cent, in locomotives is because of expanding steam to a lower pressure before exhausting, of the partial vacuum ahead of piston from condensing exhaust steam, and of the heated feed-water which should be credited to this account of efficiency of steam. I can not here go into the experiments of M. Hirn, and conclusions therefrom, on the beneficial influence of partial condensation on steam side of piston, but the above figures, so far as they go, will nearly represent the facts of efficiency. I think you will do your readers a service by correcting, even in this general way, the wrong impressions they may have received from Mr. Wahl's figures.
|John W. Cloud.|
|Altoona, Pennsylvania, July 5, 1879.|
I see by your correspondence that there is some interest taken in spiritualism.
A case occurred in my experience some fifteen years ago which, for a while, made a profound impression on my mind. My house is situated about three hundred feet from a large church, which has a fine organ, that we heard more or less, when played upon.
It was in the beginning of summer; the windows being open, myself and family heard more plainly than common, as we thought at first, the organ. It went through a chord producing at times what is called the tremolo. We soon ascertained, however, that these sounds did not come from the organ, but from the piano which stood in our double parlors. It went through a chord of quite a number of the lower notes, giving somewhat the sound of the organ. Being myself rather skeptical in matters pertaining to superhuman phenomena, I was touched profoundly by these manifestations.
Some of the more timid neighbors declared they would not live in the house; myself and family did not share these views. I stated to my friends that I expected to find some rational cause for this most extraordinary phenomenon. People wanted to come in droves to witness this new wonder, which I did not allow. Some spiritualists came from Boston, ten miles, to hear for themselves, and declared it must be produced by spirits from the other world. To this I could not assent, never having believed in spiritualism.
The Rev. Eli Fay, Unitarian, and now settled at Sheffield, England, and the Rev. Dr. J. C. Bodwell, Orthodox, now dead, both able, discreet men, spent with me considerable time in investigating the cause of these wonderful sounds. They examined the house throughout, including the cellar, without success. On one occasion one of my neighbors, being present, made the inquiry, "Who have played most on your piano, who are now dead?" My answer was, his own wife, now dead, and the daughter of one of my near neighbors. He then replied, "Is it possible that Caroline's spirit" (meaning his wife) "is there?"—when the piano seemed to go through a chord louder than ever before, and almost made the hair stand erect on our heads.
And so it continued for some days, until one evening I sat on the front stairs reading the evening paper, there being no gas burning in the house except in the hall, and my family were out. My attention was attracted to a very different sound, not musical, coming apparently from the piano. I stepped into the parlors—still the noise continued. I now lighted the gas in the parlors, when immediately the original harmony was renewed. It now occurred to me that the gas must produce some vibratory effect upon the strings of the piano and therefore was the cause of these extraordinary sounds. In support of this the sounds were heard only in the evening, which gave the whole affair an additional strangeness.
This proved to be the key that unlocked the whole mystery. I soon found the piano had nothing to do with it, notwithstanding myself and friends had repeatedly listened at the piano when the cover was both open and shut, and it seemed to proceed direct from the instrument. On further investigation the sounds were traced to the gas-meter which was in the cellar, nearly under the piano. The sound, though diffused somewhat, had seemed to be in the piano.
After a short time my family became tired of these sounds, and I had the gas meter changed for another, and have never heard them since.
I could have made a great sensation of this matter, but did not. I have no doubt that many mysterious things have taken place which have been ascribed to some supernatural cause, when persistent intelligent investigation would have solved the whole affair in a rational way.Truly,
|Woburn, Massachusetts, July 15, 1879.|