Arizona republican., 1901-09-30
"NATURE'S REVENGE"
That's What "Farmer' Dunn
 Calls a Heat Wave
The Effect of Irrigation Upon Tenn peratures Refutation of MT. Dunn's Theory by MT. Wm. G. Burns of Phoenix.

bSNlA itNSiNSA ct tliiS OiiASC IT OAiA -'iis Wm. G. Burns, section director of the !! weather bureau. concerning a fanciful i theory advanced by E. B. Dunn re- Sarding the effect of irrigation upon temperature. For many years MT. Dunn was regarded as the chief expert Of the weather bureau and in consequences the article to which reference is male by Mir. Burns. and which follows, has attracted wide attention:
 To the Editor of The Republican, Sir: I take the liberty of inviting your attention, and through you the atten- tion of the press of Arizona. to the en- closed article published in the Evening Star, Washington. D. C., on September [. 1901. entitled Natures Revenge, and to the following leaders. That's What Farmer Dunn Calls Hot Wave. Great Heat Follows Irrigation," etc. In view of the wide influence and cir culation of the Star and other news papers in which the article appears, the former prominence of the writer and its manifest injury to the cause of irrigation. if his theory be accepted. it is incumbent upon every advocate of irrigation for the sub-arid west to re- pudiate his fallacious theory as un- sound, untenable and unscientific. and in making this sweeping condemnation I desire to state that 1 am supported by the entire scientific staff of the T.. s. weather bureau, that condemns the theory set forth as being absurd,
 A denial of a theory without q req sonable argument appeals to no invest isator Of natures phenomena. In this instance there is such a variance be tween Mir. Dunn's theory of "heat waves and the generally accepted one of meteoroiogists that there is not q single pa,allelism. and the only course remaining is to condemn, and then sub stitute a rational and acce pted theory. During midsummer when the hot weather has reached it's maximum the interior of the continent becomes heat ed. wl.iie the surface of the ocean is comparatively cool. The air over the surface of the land becomes attenuated and superheated. forming a relative low" of extremely weak gradient. Bearing in mind the easterly drift of | the atmosphere. which Is either retard- ed accelerated by the relative posi- lions of areas of low or high pressure. an examination and study of iscbaric lines during the heated term will dis closs the existence of a pronounced high over the Atlantic ocean. with it's ct 1ter off the southeast coast Of the United States. This immense ridge is i known as the great Atlantic .t.iigh.' and. in Its fully developed type. acts as a barrier to the easterly translation Of the air. Its movement being reta.ded or checked. the atmosphere becomes ! heated and superheated to a great depth. under the influence of the nearly vertical rays of the sun. This condition Is aggravated by southeriy winds. the running down of the south Atlantic
 high for this high is the control ling and dominating influence when tho heat wave obtains. These abnorpai | conditions of excessive temperature prevail until the ridge of high prs sssure is impinsed upon and an opening made for the normal drift of the air.
 l I shall only advert briefly to MT
 Dunns reference to the energy caused by the water vapor proceeding from l evaporated water over an irrigated ! area Fl e says: Tn the irrigated lands; the moisture to furnish energy to these Impressions is not so great. being only ! sufficient to give them formation" MT
 Dunn Is in error in his theory of tn a functions of water vapOr in the air. In the process of evaporation of water there is a storing up of energy, not an exercise of the same. and tho water vapor represents this conservation, and its latent force Is not liberated unt:l condensation takes place. ProfessSr William M. Davis of Harvard coils gs Q SdES- " HCff- Nef'OE IS COnutilstu IT. may be locked on as giving up the store of energy that was acquired from ab-
 sorbed insolation when the vayor was
 formed.'
 Water vapor producer energy on.y
 when condensatior takes place, and the
 theory that evaporation alone causes the correctional movement of a cyclone
 or low Is contrary to accepted scien-
 tific authority. Very respectfully.
 w. G. BURNS, Section Director. FARMER DUNN'S THEORY.
 There has recently afflicted the states
 west of the Mississippi river a heated spell, which, for suffering inflicted on
 human beings and for damage done to
 stock and crops. is. perhaps. unexcelle1
 in the weather records. For period
 of several weeks temperatures rangins in the neighborhood of 100 degrees have
 burnt the life out of vegetation. so thal
 the full extent of the loss wll not bt
 known for long time yet.
 Visitation of Providence" is thc
 phrase by which such calamity Is
 usually described. but careful consid
 eration of the circumstances indicates
 rather that the late destructive hot
 wave is the result of mans own de
 vices; that the work of years whereby
 he has sought to turn the land to his 1 own purposes Is now bringing about an unexpected and alarming result h
 :hort, there is sound reason for be lieving that where man has altered tn, landscape nature has followed bS changing the weather
 It has been advanced by one of th'
 leading papers of Colorado in suggest ing an increased appropriation iron
 congress for the extension of the sys
 tenn of artificial irrigation in the state. 1 west of the Mississippi river that tn, great heat waves visiting that sectioi . l are modified by the irrigation system and a further extension of these water
 ways would have an effect in prevent ing or dissipating the intense heat an.
 be the means of saving crops in th'