May 19, 1921 hopkins: problems in biocumatics 225 



of quantities. Thus, the geographical position of a continental or inter- 

 continental base station serv^es as the central unit or key from which, 

 or relative to which, continental and intercontinental tables of sea- 

 level, time, thermal or altitude constant quantities are computed as 

 a basis for making predictions for any given isophane or altitude 

 position on any continent of the northern and southern hemispheres. 

 It also serves as a basis for the establishment of any number of regional 

 and local stations as equivalent bases for the computation of regional 

 or local tables of constants. 



5. The principle of the constant and variable. This relates to the 

 study of variability with reference to a "constant" as the measure of 

 the relative intensity of the factors of variation. In other words, 

 the variation of the variable from its "constant" magnitude, is the 

 measure, in terms of time, temperature, and distance, of the intensity 

 of the controlling influence from whatever source. 



This principle is of fundamental importance because, like the de- 

 clination of the magnetic needle from its normal position, which en- 

 ables the surv^eyor to reach a desired point, the variations of a recorded 

 quantity from its "constant" enable us to determine certain desired 

 facts and evidence in comparative studies of the bioclimatic relations 

 between geographical positions, countries or continents. 



6. The principle of equivalents as related to equal unit values of 

 certain elements of the law and of the system of application, such as 

 the geographic unit constants, coincident dates in the events of dif- 

 ferent species, variations from the constant in equivalent terms of 

 time, temperature, and distance; local base stations equivalent to 

 the intercontinental base in conforming to a standard regional or 

 local variation constant. 



7. The principle of the average or norm as related to variable quan- 

 tities. 



8. The principle or law of averages as related to the compensation 

 of errors in reported dates of events, temperatures, general computa- 

 tion of data, etc. 



(Examples were given of predictions from records at an intercon- 

 tinental base station at Kanawha Farms, West Virginia, for places 

 in western Europe. These predictions consisted of dates for the 

 advance of a certain stage of spring to a large number of places in 

 the British Isles and in Germany as characterized by the date of the 

 flowering of the English hawthorn, Crataegus oxyacantha; also predic- 

 tions of bioclimatic or life zones of stations and places represented by 



