PROTECTION OF IRON AND OTHER METAL WORK. 193 
composition is thus spoken of:—" Fortunately there is a 
simple method having the sanction of more than 20 years’ 
experience by which this corrosion and its consequences 
can be prevented. The process which was invented by 
Dr. R. Angus Smith, F.R.s., Chief Inspector of Alkali Works, 
is conducted as follows :—Tie newly cast main or pipe is 
taken before oxidation has commenced, it is heated to 
about 500° Fahrenheit, and is then dipped perpendicularly 
into a bath containing a hot mixture of pitch, and heavy 
coal oil maintained at a temperature of 430° Fahrenheit. 
After a few minutes the pipe is raised and the surplus com- 
position runs off. A black shining varnish remains on both 
inside and ontside surfaces of the pipe, and even penetrates 
deeply into the pores of the iron. For the success of this 
process it is quite essential that the iron should be newly 
cast and hot.”’ | 
**In his evidence before the Royal Commission of Water 
Supply (Ibid., page 114), Mr. Robert Rawlinson, C.B., 
M. Inst. C.B., the Chairman of the Rivers Pollution Commission 
appointed in 1865, says:—“‘I have never laid down cast- 
iron mains without this varnish. Cast-iron mains that have 
not been varnished, if they have laid five or six months on 
the ground, become oxidised both inside and outside, and 
pure water coming in contact with the commenced oxida- 
tion carries it on more rapidly. If you lay a varnished 
pipe six months on the surface it will not show one particle 
of rust, except where it has been scratched or abraided by 
rubbing the varnish off. In Whitehaven, soft water from 
Lake Ennerdale acted on cast-iron pipes, and ina very few 
years those of a small diameter (three inches) were all 
tuberculed, corroded, crusted up, and filled with oxidised 
matter, but nothing of that kind has ever occurred in any 
town that I have had to do with. Atallevents where we 
have had to cut pipes in Lancaster after eight or ten years 
