December 20, 1889.] 



SCIENCE. 



429 



It is a mistake to say tliat latent heat thus liberated [from the con- 

 densed moisture] will warm the air enough to allow the condensed 

 vapor to evaporate again ; for the latent heat is completely expended 

 in the work of pushing away the air that surrounds the ascending 

 expanding mass, and therefore cannot be applied to any other task. 

 Espy made this error for a time, but afterwards corrected himself. 

 It is regrettable to see the error now revived by Ha?en." As all 

 these computations were based on commonly accepted theories, it 

 is a little difficult to connprehend these expressions. I hope to show 

 that the confusion is where it is least suspected. I am aware that 

 the ordinary theories have such a fascination, there is little hope in 

 bringing the philosophers who accept them to what the facts seem 

 to indicate ; but there are an increasingly larger number of persons 

 who have grave doubts as to the sufficiency of present meteoro- 

 logical inferences to account for the facts observed, and it is for 

 these I write, as well as to explain my position. 



The fact that there is no exchange of air en masse from one level 

 to another has been proved by the strongest arguments, and such 

 as have not been controverted. It is a great pity that this assump- 

 tion should be boldly made at this day without answering the ob- 

 jections. It seems high time to lay aside " glittering generalities," 

 and carry out our analyses to the actual conditions we observe. 

 To do this it is only necessary to set forth quantitative computa- 

 tions of the effects produced by certain inferences. I am not aware 

 that this has been attempted save once (see Science, xiii. p. 369). 

 In that case the assumptions and results were so absurd and so 

 easily controverted, that it is not surprising that no philosopher has 

 taken up that line since. 



There are two points to be made plain. First, regarding " work." 

 This is the great shibboleth of theoreticians. If there is a trouble- 

 some quantity of heat to get rid of, or the formation of vapor which 

 is the source of energy to account for, " work," and the difficulty 

 disappears. If we place a pounds of gunpowder in a cannon, and 

 •discharge a ball upward, a certain number (say, h) of foot-pounds of 

 work is done, and this can be definitely computed. If a similar 

 amount of gunpowder be strewed over a field, there is, what we 

 may call, the same potential energy present as before ; but no one 

 believes that firing the powder will carry a shot, or that a single 

 foot-pound of effective work will be done by it. This would appear 

 one of the most serious defects in modern theories. The philoso- 

 pher sits down, draws on his thinking-cap, and, seeing rain falling 

 at the rate of two inches per day, in a twinkling finds that 11,796,- 

 ■000 cubic inches of water is condensing over a single acre. Next 

 he finds a million times that in an ordinary storm, and this repre- 

 sents billions on billions of foot-pounds of energy. Is not this the 

 veriest nonsense .' What these theoreticians need most of all is to 

 transport their steam-engine, if they can find one, into the cloud 

 region, and then compute the amount of work actually made ef- 

 fective. No one, outside of these philosophers, would boil away 

 tons of water in the open air on the Atlantic coast, 'and imagine by 

 this means to obtain effective energy enough to transport a great 

 steamer across the ocean in less than six days. 



A word regarding the " using-up of the latent heat of condensa- 

 tion by doing work in pushing aside the air which surrounds the 

 ascending expanding mass." Nothing can better illustrate the 

 views just enunciated than this inference. It is universally accepted 

 that air blows toward our storms almost normally to the isobars at 

 the outside, but more and more at an angle as it approaches the 

 centre, till it becomes tangential at ten to two hundred miles from 

 the centre. This whirling column has, it is also inferred, an up- 

 ward convectional movement at the centre. It is impossible for us 

 to imagine that there is a central core, forming a convectional 

 current, and that on all sides of this there is a vertical cylin- 

 der of air pressing in on the core, and which must be pushed 

 aside ; for just beyond this core the air is whirling in the sam.e 

 ■circle, and it is believed by some that the centrifugal effect would 

 even throw this outward. This shows conclusively that there is 

 absolutely no air to push aside, and, even if there were, the work 

 needed to move it in a frictionless medium would be inappreciable. 

 Is not this inference a most weak attempt to bolster up an exceed- 

 ingly weak theory ? 



It is probable that the old inference that the sun heats up a lim- 

 ited portion of the earth's surface, and sets up a convectional current 



which ultimately results in a violent tornado, will soon disappear. 

 Professor Ferrel, one of the most ardent advocates of this inference, 

 has recently declared, that, in order that this convectional current 

 may not be broken up from the greater speed of the upper portion, 

 it is necessary to suppose that the upper part separates from the 

 lower, advances in front of the storm, and sends its gyrations 

 through a frictionless medium to the earth. Verily, to use a homely 

 but forcible and apt expression, "this is cutting oft the tail of this 

 theory close behind its ears." 



It is now known that the sun's heat has no direct effect upon air- 

 columns near the earth. We know, 



1st, That the earth becomes very hot, but the air is almost a 

 non-conductor of this heat ; and this effect extends only a few 

 inches. 



2d, That convectional currents occur only between contiguous air 

 strata, and there is no transport of air en masse by them . 



3d, On some days the air is heated thirty or more degrees above 

 the morning temperature ; but this produces no effect on the moist- 

 ure contents of the air, it does not produce any convectional cur- 

 rent, and the heat extends over a circle about a thousand miles in 

 diameter. 



4th, As a storm approaches, clouds cover the sky, and the direct 

 effect of the sun's heat is almost entirely removed. 



5th, Notwithstanding the removal of the sun's direct influence, 

 the moisture in the air is most remarkably affected. We find enor- 

 mous additions to this moisture over a region extending for hun- 

 dreds of square miles in front of the storm. Whence comes this 

 moisture } We have indubitable evidence that heat has nothing to 

 do with it. Its occurrence is entirely independent of the winds. 

 It does not descend from above, for there is ordinarily less moist- 

 ure there than below, and theory indicates an upward and not 

 downward motion. It seems to me this is one of the most impor- 

 tant points to be determined. It would seem that the moisture 

 collects in the upper regions before the storm, for the first indica- 

 tion of the storm is the high cirrus four hundred or five hundred 

 miles in advance. This shows plainly that the origin of the storm 

 is not from convectional currents beginning at the earth's surface. 

 Is there a condition in the atmosphere which is so changed upon 

 the approach of a storm that the air begins to absorb moisture ? 

 Is there an influence from the sun that only requires a slight change 

 on the advance of a storm to cause the moisture to mass itself? 

 Is there a condition in front of the storm itself that attracts moist- 

 ure directly without its transport by air or heat currents ? Does 

 the moisture come from the whole region near the storm, and mass 

 itself at it ? These are startling hypotheses, but they have much 

 to support them. Our storms come over the arid plains of the 

 West with little moisture in them. Almost suddenly, as they ap- 

 proach the more fertile valleys, there is a marked increase in the 

 moisture. Light rain begins, which becomes heavier the farther 

 east the storm moves. At times the storms move clear across 

 the country without depositing much moisture. Is this because 

 the attractive force has less power, or because it holds the 

 moisture more tenaciously, or because the air is too dry to allow 

 precipitation ? We have here what seems a most important field 

 of research, and one that promises much. H. A. Hazen. 



Washington, Dec. 13. 



INDUSTRIAL NOTES. 

 Calendars. 

 At this season, when every one is looking for a convenient cal- 

 endar for use during the coming year, there should not be over- 

 looked the various very attractive calendars, issued as advertise- 

 ments, it is true, but in which the advertising feature is not intro- 

 duced in a way to make the calendar objectionable. Among these 

 we have just seen that issued by the well-known firm of C. I. 

 Hood & Co., of sarsaparilla fame. This calendar can be had for 

 the asking at any druggist's, or is sent postpaid on receipt of 6 

 cents in stamps at the main office of the firm in Lowell, Mass. 

 The head of a young girl lithographed in fourteen colors appears 

 on the face of the card, and is an admirable example of what can 

 be done in this line of art. It is a very pretty bit of color to 

 brighten up some dark spot. 



