56 SEVENTH REPORT—1837. 
trifling compared with the importance of the object sought, and, with 
a certain expense, the security might be rendered very complete. 
On the Waste experienced by Hot and Cold Blast Iron during the 
process of Refining. Communicated by D. Musuet. 
On Preventing the Corrosion of Cast and Wrought Iron immersed in 
Salt Water. By J. B. HARTLEY. 
The author observes, “The well-known powerful and mischievous 
effects of salt water upon iron having been very strongly felt in the 
various fastenings of the gates and other machinery of the Liverpool 
Docks subjected to its action; and as a counteraction of this evil has 
long been a desirable object, many experiments having been made with 
this view, but in a great measure without success; and since the same 
destructive tendency is more or less experienced in all similar cases, 
the following very brief account of the method at present employed to 
obviate it by my father (the Engineer to the Docks), together with the 
cireumstances which gave rise to his adoption of it, may not be deemed 
uninteresting. 
“ In order to afford a greater extent of dock space to the fast increa- 
sing trade of this port, the Liverpool Dock Trustees, in 1829, purchased 
a quantity of land at the south end of the town, a part of which was 
occupied by an old tide mill and basins, called ‘ Jackson’s Mill and 
Dams;’ in taking away these dams for the purpose of forming the 
present Brunswick Dock, in the beginning of the year 1830, an old 
cast-iron sluice or clow was met with, the mouth of which was fitted 
with a lid or valve, also of cast iron, and of considerable dimensions : 
these had been immersed in the sa/t water for rather more than 25 years, 
having been put down, as found from good authority, in 1804. When 
taken up, they were incrusted with a coat of small barnacle shells, and, 
when broken, some parts of the cast iron were found to be in excellent 
preservation, and some thoroughly decomposed. The cast tron lid or 
valve was fastened to the body of the sluice by means of brass pins, 24 
inches in diameter, forming hinges on which it turned, when lifted up 
or lowered, as occasion required ; and immediately in connection with 
these pins it was that the iron was in a perfectly sound state. By some 
inadvertency all the iron-work was broken up, and sent with other old 
metal to the furnace. 
“In July of the same year (1830), another sluice, with a similar 
valve, was taken up, which had been immersed in salt water for the 
same length of time; this was also of cast iron, but the lid or valve had, 
in addition, a loop cast on to its lower edge, with which it was opened 
and shut by means of a connecting rod. The top joint or hinge of the 
valve was similar to the one previously found, that is, turning on brass 
pins, which worked in zron collars cast on to the body of the sluice ; 
