Febeuaey 21, 1902.] 



SCIENCE. 



315 



the Fresno region, where the ground water 

 originally stood forty feet below the surface, 

 while now it is at a few feet, and sometimes 

 at and above the soil surface. It is historically 

 certain that the rise of the ground water came 

 about there, as at many other points, not from 

 direct over-irrigation, but by the enormous 

 leakage of water from ditches with porous, 

 sandy bottoms and banks. From these I have 

 frequently traced the water slope sideways 

 until the auger reached a depth of ten or more 

 feet ; and the gradual rise of the water level in 

 neighboring wells, whose sides remained dry 

 save within reach of the capillary rise of the 

 water, proved plainly that the water was 

 ascending from the original level by hydro- 

 static adjustment, not by penetration from 

 above; where as a matter of fact irrigation 

 often hail not even begun. 



The extraordinary accumulation , of alkali 

 salts at the surface that has occurred in the 

 Fresno and some other regions of the San 

 Joaquin valley, are clearly due originally to 

 the leaching upward of the entire mass of 

 alkali in the sub-strata. The investigations of 

 the California Station have shown that in 

 the arid region few uplands normally contain 

 less than from 2,000 to 2,500 pounds of soluble 

 salts per acre in four feet depth; and much 

 more has been found in the silty sub-strata of 

 the Salton basin in southern California, even 

 to 22 feet depth. When all the salts thus con- 

 tained in 40 feet of material are leached to 

 the surface in addition to the accumulation 

 already existing there, the overwhelming in- 

 vasion we find where these leaky ditches exist 

 cannot surprise us. E. W. Hilgard. 



REPRINTS OF SCIENTIFIC PAPERS. 



To THE Editor of Science : Will you 

 allow me space for a word concern- 

 ing a point of professional courtesy? It 

 arose in connection with a personal experi- 

 ence. The incident is wholly trivial, namely, 

 the failure of the publishers, or editor, of the 

 Neiv York Teachers' Monographs to furnish 

 the reprints promised of an article which ap- 

 peared in the October number. 



It is the custom of writers on technical sci- 

 ence to exchange copies of their published 



monographs. The brochure is sent frequently 

 with an explicit — and always with at least 

 the implied — request for a similar courtesy in 

 return, upon the appearance of anything of 

 the receiver's own in print. The relation thus 

 becomes one of simple duty, which may not be 

 considered or disregarded at will. To each of 

 his correspondents one owes a debt which is 

 discharged only when copies of his own pub- 

 lished work have been sent in exchange. 



But the matter goes deeper. The contribu- 

 tor to technical scientific periodicals is rarely, 

 if ever, paid for his writings. These publica- 

 tions, in many instances founded and support- 

 ed by associations of scientific students, are 

 not primarily commercial enterprises, but 

 vehicles of communication among scholars 

 having common interests and aims. They are 

 means by which is made possible the publica- 

 tion of monographic literature, the printing 

 of which, in the majority of cases, would be 

 too heavy a burden for the individual writer. 

 It is part of the meaning of these technical 

 journals' existence that the process of thus 

 communicating- scientific thought shall be fa- 

 cilitated as greatly as possible. 



This function has been very widely and 

 generously recognized by the publishers of our 

 reputable scientific periodicals in America. It 

 is expressed in the custom of presenting to 

 each substantial contributor a larger or small- 

 er number of separately bound reprints of his 

 article for distribution. Upon the free ex- 

 change of monographs which thus becomes 

 possible the scholar depends in no small de- 

 gree for the equipment of his working library ; 

 for this literature, which represents the points 

 of immediate growth in special lines of 

 thought, finds its way only slowly and incom- 

 pletely into permanent print. It is, therefore, 

 a matter of serious and general importance 

 that these relations between contributor and 

 publisher should be cordially maintained, and 

 the flagrant infraction of them should not re- 

 main unknown. Egbert MacDougall. 



jSTew York "Univeksity. 



the SACRAMENTO FORESTS OF NEW MEXICO. 



To THE Editor of Science : In a communi- 

 cation to your paper dated November 8, 1901, 



