434 



tion from this water made a practical saturation, as indicated by the 

 almost continual presence of condensation on the walls. Experiments of 

 this type were not ventilated. The rate of flow of air through the experi- 

 mental bottles was determined by the use of the Ellison diflferential gage 

 and diaphragm chambers. A 2 mm. aperture and 5 mm. reading were 

 used in the standard experiments, but the rate of air flow was not checked 

 up as closely as it should have been in the earlier experiments, because 

 various difficulties with the equipment rendered it impracticable to make 

 frequent measurements. This commonly gave a flow of a little more 

 than one mm. per second through the bottle. A series of variable-tem- 

 perature experiments was run with paired larval containers simply placed 

 out of doors, or in a greenhouse, or in the experimental case where 

 various chinch-bug experiments were being made and many data were 

 being reported. The experiments with light were made with single 

 containers under conditions as described on p. 427 Table Xlllg (p. 372). 



D. Recording of Data. 



Records of experimental work were copied on large sheets, legal size, 

 Syi by 14, printed with a special heading bearing the name of the survey 

 and calling for the name of the observer in the upper right hand corner, 

 with experiment number, date, and species immediately below this; while 

 at the right of the center were the words "Subject of Experiments." 

 Below this was the description of apparatus, and a line calling for notes 

 on light and temperatures, together with previous history and condition 

 of the stock. The lower 11 inches of this paper was ruled horizontally at 

 quarter-inch intervals, with 21 vertical rulings at ^-inch intervals, and 

 leaving a square space of one-half inch at each margin. Down the center 

 of the page was a double blue ruling, which constituted one of the equi- 

 distant sets, and, on each side of this, three red rulings, which constituted 

 three of the equidistant sets. This type of paper was found to be par- 

 ticularly useful where a large number of individuals had to be checked 

 up, as the numbers were put at the heads of the vertical columns and 

 the dates in the left-hand margins, the checkings in each square to show 

 the condition of the individuals from day to day. The upper left-hand 

 corner of this paper was clear of printing or writing for the equivalent 

 of a triangle with its sides three inches. This left a space in which no 

 writing was ever placed, which made easy the fastening together of the 

 sheets with various types of clips without interfering with the writing of 

 the notes. These were got up for the current experiments and placed on 

 legal size board clips, which the investigator carried about with him as 

 he observed the conditions of the experiments from day to day. The 

 difi^erent chambers in which these experiments were going on were let- 

 tered, beginning with the large constant-temperature rooms, which were 

 lettered A and B ; then the variable units, lettered C, D. E, F, and G, as 

 already noted ; then the smaller units inside the constant-temperature 

 rooms, lettered H, I, L, and V (the intervening letters having been used 



