(333) 



was set up on May 4, and In digging the holes for the soil ther- 

 mometers, frozen ground was encountered a few inches below the 

 surface. The Ithaca stations were established May 12. All the 

 stations were read once a week on the same day until October 5, 

 except for the Cranberry Lake station which was discontinued 

 after September 21. 



All the records have been plotted on cross-section paper so as to 

 bring out the relations between the different stations graphically. 

 For each environmental factor, all the New York stations were 

 plotted together, but without the other stations, in order to show 

 the relations between conditions in the open, in the hemlock 

 forest, and in the hardwoods. On another set of charts were 

 plotted for each factor, the two New Haven stations, the two 

 Ithaca stations, Cranberry Lake, and the New York hemlock 

 station. All these stations, it will be noticed, were in the hemlock 

 type, except the hardwoods at Ithaca. Therefore this second set 

 of charts should show the environmental relations between 

 examples of the hemlock type in different parts of its range. 

 They should give us a picture of the differences between certain 

 environmental factors in diiferent hemlock forests. With the 

 range of conditions covered we should have some indication of 

 range of requirements of the type. Since the records cover only a 

 single season, it is impossible to say that they represent definite 

 limits, but they do have a distinct relative value, and bring out 

 some rather interesting and unexpected relationships. 



The plotting of these two sets of charts for each factor which 

 had to be examined required the plotting of a total of 24 charts, 

 including 120 curves.^ It will be impossible to reproduce more 

 than a limited number of charts which are typical, or illustrate 

 special features. The detailed records are also too voluminous to 

 publish in full, so only the totals and averages will be presented.'^ 



Evaporation 

 The average daily evaporation for each week from May 12th to 

 October 5th at the four stations on The New York Botanical 

 Garden grounds is shown graphically in figure i. The relation- 



^ For this laborious and painstaking task thanks are due to Miss Hester M. Rusk 

 of The New York Botanical Garden staff. 



^ The records are on file at The New York Botanical Garden, which will furnish 

 copies to qualified persons at the cost of reproduction. 



