This Sample Was Rejected. Analysis Of A Further Sample

Per cent.

Oil ••• ••• • • • . . . . . . . . .

23.45

Turpentine ... ............

3.50

Pigment ...............

73.05

100.00

Analysis Of The Pigment

Per cent.

White lead ...

95.54

Carbon

1.72

Insoluble siliceous matter ...

1.58

Ferric oxide and alumina ...

0.46

Lime

Nil.

99.30

This sample was accepted.

For the preservation of steel surfaces exposed to corrosion by prolonged immersion in sea water, especially in positions difficult of access, various kinds of cements have been used. The composition of the cement referred to in Chap. VI., p. 402, and used as a coating in the bilges of caissons and other similar situations, is as follows:-

Mineral pitch...

250 lbs.

Mineral tar

6 gallons

Roman cement

360 lbs.

Lime, fine white

56 „

Resin, fine black

14 „

Oil of naphtha, or black naphtha ...

1 gallon

This composition gave an approximate weight of 102 lbs. per cubic foot, and formed a hard tenacious coating with an excellent surface, when applied to steel plates.