426 VALUATION, DEPRECIATION AND THE RATE-BASE 
TABLE 30. THE PROBABLE USEFUL LIFE OF VARIOUS 
ARTICLES (Continued) 
Description. Ep Revidonl Authority. Remarks. 
Years 
Poles 
wooden in concrete........ 20 Wis. R. R. Com. Quoted by Henry Floy. 
cedar. lL Jl us hele ET | 167 ft. P. G. & E. Co. S. F. rate hearing 1913-14. 
cedar with cross arms..... I2 | 0% Wis. R. R. Com. Wisconsin Tel. Co. Case. 
cedar under 35’ long....... I0-I5 0% Tel. “Data” Quoted by H. A. Foster. 
cedar 35’ long and over.... 15-20 0% Tel. “ Data” Quoted by H. A. Foster. 
cedarinearth............. 10-18 Foster ‘ Eng. Valuation,” etc. 
cedar in concrete. ......... 12-20 Foster *“ Eng. Valuation,” etc. 
chestnut under 35’ long.... 8-12 Tel. Data” Quoted by H. A. Foster. 
chestnut 35’ and over...... I2-1I5 Tel. * Data” Quoted by H. A. Foster. 
pine-creosoted.............. 20 Tel. Data’ Quoted by H. A. Foster. 
FeGwOod.. iu asin tes navel 10 BiOf-z5g LP. G. & E. Co. S. F. rate hearing, 1913-14. 
LELOPIONR. vis vs 9s 55 0k =o REET] Wis. R. R. Com Quoted by H. A. Foster. 
telephone cross arms. .....| 8-12 Wis. R. R. Com. Quoted by H. A. Foster. 
average exchange.......... 10 0% Tel. “Data” Quoted by H. A. Foster. 
average toll... LLL 15 0% Tel. “Data” Quoted by H. A. Foster. 
ATROTY d eehule he adnate tibet une 20 Chi... -iCo. Chi. Union Trac. Co. Case. 
TOOT 4a af ela tare ales to Joule nis skal ete 40 Wis. R. R. Com Milwaukee 3¢ Fare Case. 
FTO lls lal ieteiale atatati tis mints EAC Arnold 4 Chicago Appraisals. 
Steel. on sa RA a EE SO Floy ard Ave. Case, N. Y. City 
Power plant equipment. ...... 12} Cooley Milwaukee 3¢ Fare Case. 
20 Starrett Milwaukee 3¢ Fare Case. 
21.0X Wis. R. R. Com Milwaukee 3¢ Fare Case. 
I I AE 15 St. [LiP.'S. C. Union Elec. L. & P. Co. Case. 
20 Floy ard Ave. Case, N. Y. City. 
20 Trac. Val. Com. Chi. Con. Trac. Co. Case. 
20 Arnold Coney Isl. & Brooklyn Case. 
20 Arnold 4 Chicago Appraisals. 
20 Arbitrators Ata. St. Ltg. Controversy. 
21.3 Alvord Proc. Am. W. W. Assoc., 1903. 
22 Rosecrans Galena Appraisal, Kan., 1905. 
25 Hammond Jour. Inst. Elec. E., 1907. 
25 6% Preece Report Bristol Corp., 1906. 
25-30 Williams Galena Appraisal, Kan., 1905. 
30 Kiersted Galena Appraisal, Kan., 1905. 
30 Burdick Mt. Vernon W. W., Ill., 1906. 
40 Dodge Mt. Vernon W. W., Ill., 1906. 
and auxiliary machinery.. 20-30 Metcalf Trans. Am. Soc. C. E., 1909. 
and condensers............| I5-25 Wis. R. R. Com. Milwaukee 3¢ Fare Case. 
small steam...............| IS Wis. R. R. Com. Quoted by Henry Floy. 
general service.............1 16 | 5% P.G.&E. Co. S. F. rate hearings, 1913-14. 
centrifugal ou ties ioe nies 16 5% D.G.&E.Co. S.F.rate hearings, 1913-14. 
centrifugal ............... 20-30 Foster ‘Eng. Valuation," etc. 
geared pOWer.......:..... 20-30 Foster ‘“ Eng. Valuation,” etc. 
Botler feed... is al der ET 520 Foster “Eng. Valuation,” etc. 
of] Lr CS dtr 16 | 5% P.G.&E. Co. S. F. rate hearings, 1913-14. 
Purifiers 
gas—modern.......oeenn- 50 Wis. R. R. Com Quoted by H. A. Foster. 
ReServoirs. ......oovaveesess. 50-I00: Metcalf Trans. Am. Soc. C. E., 1909. 
100 Burdick Mt. Vernon W. W., Ill., 1906.