184 



The Philippine Journal of Science 



1916 



the zinc has been dissolved, and when that point is reached, 

 the acid solution is considerably weakened, so that the loss of 

 iron is doubtless considerably lower than is indicated by the 

 S-minute or 10-minute immersion tests. However, the alloyed- 

 iron determination is useful for purposes of comparison and 

 is valuable, even though it may be more or less approximate. 

 The lead and alloyed iron found in the coating of some of the 

 old and the modern galvanized sheets are shown in Table V. 



Table V. — Lead and alloyed iron'^ in coating of galvanized iron. 



A. ON OLD GALVANIZED SHEETS. 



Brand. 



Zinc per 

 square 

 decime- 

 ter. 



Lead in coating. 



1 

 Iron in coating. 



Per 

 square 

 decime- 

 ter. 



Lead 

 Zinc 



Per 

 square 

 decime- 

 ter. 



Iron 

 Zinc 



1-X- 



Grams. 

 8.33 

 11.02 

 9.98 

 8.69 

 8.42 

 12.63 

 10.15 



Grants. 

 0. 0701 

 0. 0857 

 0.0509 

 0.0406 

 0.0601 

 0.0889 

 0.0893 



Per cent. 

 0.84 

 0.78 

 0.51 

 0.47 

 0.71 

 0.62 

 0.88 



Grams. 



0.3081 

 0. 3132 

 0.3316 

 0. 4623 

 0.3040 

 0.4591 

 0.3375 



Per cent. 

 3.70 

 2.84 

 3.32 

 6.32 

 3.61 

 3.64 

 3.32 



2-X .- . 



3-X 



4-X 



5-X .__ 



6-X __ 



8-X 





B. ON MODERN GALVANIZED SHEETS. 



A-2 . - — 



6.36 

 4.91 

 4.71 

 5.80 

 4.58 

 4.07 

 4.31 

 4.74 

 3.71 

 3.58 

 7.51 

 3.41 

 6.50 



0.0171 

 0.0293 

 0.0231 

 0.0340 

 0.0253 

 0.0240 

 0. 0253 

 0. 0199 

 0.0340 

 0. 0187 

 0.0546 

 0. 0192 

 0. 0540 



0.27 

 0.59 

 0.49 

 0.59 

 0.55 

 0.59 

 0.59 

 0.42 

 0.91 

 0.52 

 0.73 

 0.56 

 0.98 



0. 1982 

 0.1926 

 0.2302 

 0.2293 

 0. 1822 

 0. 1811 

 0. 1475 

 0.1287 

 0.2032 

 0. 3730 

 0. 1768 

 0. 1731 

 0.2272 



3.12 



3.92 

 4.88 

 3.59 

 3.98 

 4.45 

 3.42 

 2.72 : 

 5.48 

 10.42 

 2.35 

 5.08 

 3.49 



A-3 . — - 



B-1 . . .- -- 



C-1 



C-2 - . 



D-1 .. . 



D-3 



E-2 



E-1 



F 



G : 



H 



I . . 





" Dissolved in 3 per cent sulphuric acid. 



Though no great accuracy is claimed for the analytical data 

 on the amounts of iron alloyed with the zinc, they show clearly 

 that the old sheets contained more iron in the coating than did 

 the new; hence the better service of the old sheets cannot be 

 ascribed to greater purity of coating, with respect to alloyed 

 iron. 



Although most of the modern galvanized sheets contained 



