July 14, 1905.] 



SCIENCE. 



55 



pared the index for 1904, and will hope that 

 he may have time next year to make a more 

 complete index for the 1905 volume. 



CLIMATE OF JERUSALEM. 



Professor G. Arvanitakis, in the Bulletin 

 de TInstitut Egyptien (4th ser., No. 49), has 

 published a series of meteorological observa- 

 tions taken at Jerusalem, as well as some notes 

 on the climate of that region. The winds 

 from the east are extremely dry, coming as 

 they do from • the Arabian deserts. Rain 

 comes from the western quadrants. Hail is 

 noted as being fairly common in Palestine, 

 and a source of injury to the fruits. The ob- 

 server says that he seldom saw a heavy rain- 

 fall unaccompanied by hail. Cisterns and 

 reservoirs supply water during the dry season 

 of summer, and the heavy dews are very bene- 

 ficial to vegetation. These dews are character- 

 istic of Palestine, and must be seen to be fully 

 appreciated. The climate is not described as 

 very healthful. Dysentery, fever and rheuma- 

 tism are not uncommon at Jerusalem, espe- 

 cially during the summer months. 



MARINE meteorological SERVICE OF CHILE. 



The meteorological work carried on at the 

 coast stations of Chile, from Arica in the 

 north to the Strait of Magellan in the south, 

 is under the direction of the so-called ' Direc- 

 cion del Territorio Maritimo ' of Chile. Up 

 to the year 1899 this work was in charge of 

 the central observatory at Santiago. An an- 

 nual volume (Aniiario) is issued, giving com- 

 plete tabulations of the data for each of the 

 eighteen stations, and including monthly and 

 annual summaries. Thus far (1903, Vol. V., 

 issued 1904) no discussion of these observa- 

 tions has been included. These littoral sta- 

 tions of Chile have the great advantage of 

 varying but little in their longitude, and of 

 being very near sea level, so that there is much 

 uniformity in these respects. The great cli- 

 matic interest of Chile, which results from its 

 peculiar position with reference to the Cor- 

 dillera of South America, and from its extra- 

 ordinary contrasts in rainfall between the arid 

 north and the rainy south, lends exceptional 



value to any such data as those included in the 

 volumes here considered. 



R. DeC. Ward. 



l^'OTES ON FORESTRY. 

 WHY PRAIRIES ARE TREELESS. 



In a paper by Alfred Gaskill read before 

 The Society of American Foresters, February 

 23, the theory that forest fires are responsible 

 for > the treeless condition of the prairies was 

 advocated. In support of this by no means new 

 theory, Mr. Gaskill cited some geological, 

 physiographical, climatological and silvical 

 facts which, in his opinion, point most em- 

 phatically to the fire origin of all true 

 prairies. He divides the treeless area in the 

 United States into plains and prairie. The 

 former are treeless, primarily because of 

 deficient moisture, and were so from time 

 immemorial. It is different, however, with 

 the prairies; they offer conditions favorable 

 to tree growth and, therefore, their treeless 

 condition presents a riddle clamoring for 

 solution. The great prairie of the United 

 States occupies an irregular area bounded 

 on the east by a line that follows in a 

 general way the ninety-fifth meridian and on 

 the west by a line roughly extending along the 

 ninety-seventh meridian. The eastern bound- 

 ary is most irregular, its shape corroborating 

 the fire origin of the prairie. In the north 

 it makes a great bend eastward, enclosing half 

 of Iowa, more than half of Illinois, and por- 

 tions of Wisconsin and Indiana. Along its 

 whole extension the prairie forms lobes and 

 long tongues thrusting eastward into the for- 

 est. Since it is proved by the records of the 

 Weather Bureau that the western boundary is 

 within the limit of sufficient rainfall, capable 

 of supporting tree growth, the whole area now 

 occupied by the prairie is situated where for- 

 est ought to be, for there is neither lack of 

 rain nor any condition in the soil or the 

 vegetation that will account for the absence 

 of trees. Mr. Gaskill assumes, therefore, that 

 something not entirely normal caused the for- 

 est to retreat from its proper position. After 

 a careful and detailed study of the records 

 of forest and prairie fires in the states of 

 Montana, Wyoming, Colorado, Texas, South 



