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problems who have held that the average maximum temperatures 
were the controlling factors, these were taken. But here again 
the comparative equality could offer no satisfactory solution, 
as in both places the maximum was about 90 
Reversing the process, and taking the average minimum tem- 
peratures, a procedure followed by still others, netted more sug- 
* gestive results. The differences here were considerable, as the 
average minimum at Windham in the Catskills is — 12°, while 
at Cape May in southern New Jersey it is 8°, a discrepancy of 
» about 20°. This, however, is vitiated by the protective nature 
of the snow blanket which covers the colder region for the 
greater part of the winter; an advantage lacking in lower New 
Jersey, where, however, the increased temperatures during winter 
about equalize matters. Then, too, it has been shown that seeds 
can stand artificial temperatures enormously lower than are ever 
found in nature, so that plants which rely on their seeds for per- 
petuation must be indifferent to any natural minima. Against 
this average minimum temperature as a delimiting factor in the 
distribution of our local plants, is the protective dormancy of all 
the woody plants in the region, during the cold weather. These 
objections are sufficient to render the theory incompetent, and 
it was abandone 
Merriam’s “ife zones,’ an attempt to plot out the more promi- 
nent belts of animal and vegetable life in North America upon 
the basis of temperature, was found to come more nearly to the 
known facts of the distribution of our local plants, than any of 
the above hypotheses. But while its general principles were 
found to hold good, the difficulty of using a scheme of continental 
scope upon a limited area was such that accuracy seemed unlikely. 
any investigators have thought that some method of using 
the accumulated temperatures of a part of a season, or of all of 
it, would throw some light on the problem, but the dangers 
here are many and have been well summarized in Warming’s 
“Oecology of Plants,” page 26. 
At the suggestion of Dr. C. Stuart Gager a new phase of the 
problem was then investigated. The method of the Department 
of Agriculture in their work on the acclimatization of wheat 
