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 gji x 7^ inches. The record book is the usual note-book cover, which 

 has been found neither too large 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. i, is most satisfactory for 

 inking; drawing pens, such as Gillott's Crowquill, are too finely pointed for 

 ordinary use. 



