Si MIGRATION AND BUSINESS CYCLES 
index of factory employment published by the U. S. Bureau of 
Labor Statistics, for the years 1915 to 1924. To obtain the final 
estimate, which appears as Curve (c) in Chart 54, Fig. A, an average 
of the two indices was taken. 
CHART 52 
EVIDENCE OF SEASONAL VARIATION IN EMPLOYMENT IN SELECTED 
INDUSTRIES" 
Average of twelve months= 100 
Fig.A- FACTORY EMPLOYMENT Fig.B- RAILWAY MAINTENANCE 
1020 = g | 20r g 
= 2 es Selected States 
: ¢ : 
1010 i : 110, 
— 
100015" 100+ 
| ¢ 
990} 90 | Cy 
| ) \ ; | ce——o=Expenditures \) 
bo—o= United States . rt do—o= Section Laborers 
OTF Iv aw [sv Tals [ovo] OA Iw ATM Tv a TS To TaTH 
Fig.C - BITUMINOUS COAL MINING Fig.D-ANTHRACITE COAL MINING 
- — TT 1 rr or = 
208 Co—-0= Production 208 Tr 
i fo—o= Employment 
110 110 
: Ta ly 
= Sn] 2 »—0 
100H— oo = Emre Ee =e 
e 2 ? 
po 2 mle 
ge--—-e= Production Le 
wi por he---<= Employment, 1909 
I —o= Employment; 1919 
SOF Im am 71IT4T5 [0]~]D SO FTF Tw [4 li | 417 [4] 56ND] 
sFor fuller statement of the nature and sources of the data used in constructing 
curves “a” to “g”, see Table 56. Curves “h” and “i” represent the average number of 
men employed in anthracite mines in the census years 1909 and 1919. Thirteenth 
Census of the United States, Vol. XI, p. 196; Fourteenth Census, XI, p. 278. 
As indicated by this estimate, factory employment exhibits a 
spring boom, a midsummer slump, a fall boom, and another slump 
in midwinter. 
Railway Maintenance (Chart 52, Fig. B). 
Many foreign-born workers are engaged as section hands in the 
maintenance of railway tracks and roadbeds. As a measure of 
99