PHYSICAL FACTOR RESULTS 95 
many observations, the tendency to take notes or to record observations 
rapidly is very great, but this will correct itself after a few attempts to 
use such notes. The record forms for various factors have been indicated 
in the proper place, as well as the one for simultaneous readings. Ecograph 
sheets are carefully filed, and constitute permanent records. With a little 
practice they may be read almost as easily as tables, and any attempt to 
put them into tabular form is a mere waste of time. For purposes of study 
and of publication, it often becomes necessary to bring together all the 
results obtained for a particular habitat, both by simple instruments and by 
ecographs. The form of record used for this is essentially that already 
indicated for simultaneous readings on page 92, since general features and 
constant factors can not well be included in the table. Record sheets of 
this type have been printed at a cost of $5 per thousand, and the various 
factor records can be obtained at about the same rate. The size of sheet 
used is 934 x 734 inches. The record book is the usual note-book cover, which 
has been found neither too largé nor too small. It is protected from dirt 
and rain by a covering of oilcloth which overlaps the edges. Record books 
should be carefully labeled, and each one should contain a single year’s 
records. 
Factor Curves 
139. Plotting. The paper employed is divided into centimeter squares 
which are subdivided into 2-millimeter units. For ordinary curves the 
size of sheet is 9% x 734 inches, which makes it possible for curve sheets to 
be filed in the record book. Tablets containing 60 of these sheets can be 
obtained for 20 cents each from the Central School Supply House, Chicago. 
For curves longer than 9 inches special sizes of sheets must be used. On 
account of their inconvenience large sheets are avoided whenever possible. 
This can usually be accomplished by increasing the numerical value of the 
intervals. The inks employed in plotting are the waterproof inks of Chas. 
Higgins & Co., Brooklyn, New York. These are made in ten or more 
colors, black, violet, indigo, blue, green, yellow, orange, brown, brick red, 
carmine, and scarlet, and cost 25 cents per bottle. In addition to being 
waterproof, they make it possible to combine curves in all conceivable 
ways without destroying their identity. Furthermore, it is a great advan- 
tage to use the same color invariably for the same kind of curve: thus, 
it has been the practice to indicate the 3-foot, surface, 5, 10, and 15-inch 
temperature curves by violet, green, yellow, blue, and carmine respectively. 
A fine-pointed pen, such as the Spencerian No. 1, is most satisfactory for 
inking; drawing pens, such as Gillott’s Crowquill, are too finely pointed for 
ordinary use. 
