424 VALUATION, DEPRECIATION AND THE RATE-BASE 
TABLE 30. THE PROBABLE USEFUL LIFE OF VARIOUS 
ARTICLES (Continued) 
Description. Hi oo Be hd | Authority. Remarks. 
Years 
Head gates 
oniditches... LLRs 30 S.J.L.&P. Cor. Cal. R.R. Com. rate hearing. 
Heaters (feed water) ......... 15 C. UT. Co. Chi. Union Trac. Co. Case. 
20 Stone & Webs. Chi. Union Trac. Co. Case. 
20 P. G.&E. Co. S. F. rate hearings, 1913-14. 
16-25 Trac. Val. Com. Chicago Con. Trac. Co. Case. 
15-30 Wis. R. R. Com Milwaukee 3¢ Fare Case. 
30 Wis. R. R. Com Quoted by Henry Floy. 
33% Arnold 4 Chicago Appraisals. 
Lamps 
ATCA i ah 63 Arbitrators Ata. St. Lgt. Controversy. 
ATC LAC Tai 12 5% Preece Report Bristol Corp., 1906. 
ATCA AE SLII Ls Sl 12% St. L. P. S.C. Union Elec. L. & P. Co. Case. 
arc un ni LTS P. G. & E. Co. S. F. rate hearings, 1913-14. 
BEC ER LA la 15 Wis. R. R. Com. Quoted by Henry Floy. 
Nernst. cL tu bhai 8-10 Foster “ Eng. Valuation,” etc. 
arc lamp posts. ............, 40 5% Preece Report Bristol Corp., 1906. 
Lighting systems 
incandescent street........ 15 P. G. & E. Co. S. F. rate hearings, 1913-14. 
arc (commercial & mun.).. 15 P. G. & E. Co. S. F. rate hearings, 1913-14. 
municipal street...........; 20 5% Cal. R. R. Com. Calis. E. C.vs. NapaVal.E. C. 
Lighting protection. ........... 10 P. G. & E. Co. S. F. rate hearings, 1913-14. 
15 S.].L.&P. Cor. Cal. R.R. Com. rate hearing. 
15-20 Foster “ Eng. Valuation,” etc. 
10-12 Foster “ Eng. Valuation," etc. 
Machinery... iodine 27 6% Parsons Jour. Inst. Elec. E., 1907. 
engines and machinery... 25 6% Preece Report Bristol Corp., 1906. 
Meters 
electric, LL all 10 Hammond Jour. Inst. Elec. E., 1907. 
electric. (Liat Al iil, 12 29, Preece Report Bristol Corp., 1906. 
electric! fi. Jel de salah 12 59% Parsons Jour. Inst. Elec. E., 1907. 
electrict iia ve 32, 5 St... PS. C. Union Elec. L. &P. Co. Case. 
RleobTIC | Cd laine 15 P. G. & E. Co. S. F. rate hearings, 1913-14. 
electric il inet. 23.6 10% Cal. R. R. Com. Calis. E. C.vs.Napa Val.E. C. 
electric-switchboard. ...... 20 Wis. R. R. Com. Quoted by Henry Floy. 
electric Service. ...... out 15 Wis. R. R. Com. Quoted by Henry Floy. 
gas-station (drums).......1 20 Wis. R. R. Com. Quoted by H. A. Foster. 
gas-station (cases)......... 50 Wis. R. R. Com. Quoted by H. A. Foster. 
gAS-CONSUIMETS. ..«cuvneene- 25 Wis. R. R. Com Quoted by H. A. Foster. 
water. lal noob 20 Williams Galena Appraisal, Kan., 1905. 
Water! Lh dn i 20-30 Metcalf Trans. Am. Soc. C. E., 1909. 
water. . iu 50 Cal. R. R. Com. Cuyumaca W. Co. Case. 
POUND. Sie dats lls insinuate lets 10 Mil. E. R. & L. Milwaukee 3¢ Fare Case. 
10 Cooley Milwaukee 3¢ Fare Case. 
12.5 Starrett Milwaukee 3¢ Fare Case. 
10-12.5 Wis. R. R. Com Milwaukee 3¢ Fare Case. 
10-26 Stone & Webs. Chi. Union Trac. Co. Case. 
10-25 Chi. U. T. Co: Chi. Union Trac. Co. Case. 
asphalt... Jol ee ey 10 Chi. U. T. Co. Chi. Union Trac. Co. Case. 
asphalt... lesser enisnn 10 Stone & Webs. Chi. Union Trac. Co. Case.