24 The Ohio Journal of Science [Vol. XIX, No. 1, 



incident to exposure under different climatic conditions. The 

 instruments we used were of the non-absorbing or "rain-proof" 

 type, but the new spherical cups had not yet been supplied to 

 correct for variations in the angle of incidence of the sun's rays. 

 The following example will, however, convey some idea of the 

 relative evaporation at Kodiak and in the northern United 

 States. Transeau 20 , in the pioneer work of this sort, found an 

 average daily rate of evaporation of 19.72 ccm. at his base 

 station, the Garden of the Carnegie Institution at Cold Spring 

 Harbor, Long Island, New York, as compared with 6.83 ccm. 

 at Kodiak. This station at sea level near the ocean is in a 

 general way comparable with Kodiak. But his instruments 

 were of the old rain absorbing type, and the cup was set close 

 to the ground, whereas ours was set about a meter above the 

 ground. Both of these facts would tend to increase the differ- 

 ence between the rates at the two places. 



THE VEGETATION STATIONS. 



At the inception of the work, it was recognized that the 

 restoration of the plant cover was a process that would probably 

 require several decades for its completion. It was deemed 

 essential to a proper record of the progress of events that a 

 series of permanent vegetation stations of some sort be estab- 

 lished in which the future student might find areas whose exact 

 history is known from the period of the eruption. The selection 

 of the type of such vegetation stations and the best way of 

 locating them were, therefore, among the first problems to be 

 solved at the beginning of the investigation. 



In the course of the work about one hundred definite vegeta- 

 tion stations have been established, partly in the vicinity of 

 Kodiak, partly on the mainland. Some of these have already 

 served the purpose of their establishment and observation of 

 them has been discontinued. At others the anticipated begin- 

 nings of vegetation will not start for some years. Repeated 

 observations through three consecutive years have now been 

 made at more than half of these stations. In some cases the 

 photographic records include five years, dating back to 1913 or 

 even to 1912. 



20 Transeau, E. N. The Relation of Plant Societies to Evaporation. Bot. Gaz. 

 45: 217-231. 1908. 



