124 JOHN BERRY HAYCRAFT ON 
March, = 566 
April, = 634 
May, = 473 
June, = 1430 
July, = 1097 
August, = 664 
September, = 664 
October, = 649 
November, = 933 
December, = 919 
It is, in short, a curve with two maxima; one occurring in November, 
December, and January, and the other in June and July. 
We shall now endeavour to investigate its influence upon the conception 
curve. Influence it must have,—the interesting point is the average interval 
between marriage and conception. 
The best plan-—having found out that RAS is a factor—is to sub- 
tract from the conception curve the temperature influence, and to study the 
resulting figures or curve which may be formed from them in connection with 
the marriage curve. 
Find out the monthly average temperature, and in relation to this average 
express the other monthly numbers as + or — quantities. For example, the 
average monthly temperature is 47:1, and in January it is 38°5; therefore 
January will be 38:5 — 47:1 = — 8°6 (see Col. L.). 
De this for all the periods in the temperature and conception curves (see 
Cols. I. and ITI.): 
Now add up all the minus quantities of both columns, and divide the result- 
ing conception by the temperature numbers, which will give 18. 
Multiply the numbers in the temperature column (Col. I.) by this number 
18, which will give Column IT. 
Now that the temperature curve is so multiplied, it can be subtracted from 
the conception curve ; this gives Column IV., which is the resulting conception 
curve from which all temperature has been subtracted. 
Col. I. Col. II. Col. III. Col. III. 
January, = — 86 x 18 = — 155 subtracted from — 55 = + 100 
February, = — 74 Pe — 133 z » = 126 + 7 
March, =— 63 Ks Sees ig le) . fo le + 36 
April, =— 10 " — 18 i Po oF + 45 
May, =e -) + 238 x » — 70 — 108 
June, = —£° 86 ; + 155 3 ME LROn ve, 255 
July, —\stsalieD Aeneas 212 Ne job 260... cena 
August, = + 10°7 ‘3 + 193 ~ » + 163 — 30 
