TRANSACTIONS OF THE SECTIONS. 57 
_ the lower joint or loop was bushed with brass, through which a large 
_ wrought-iron pin passed, forming the joint between the connecting rod 
and the valve. 
“All the parts of the ron immediately around the brass were in this, 
as in the former case, in ewcellent preservation; the wrought-cron pin 
was corroded a little, but not materially ; yet, had it been suspended in 
a similar manner by itself, or in connection with iron stone, there can 
be little doubt but that it would have been, in a great measure, if not 
wholly, destroyed. The cast iron near to the brass retains its original 
soundness, but became gradually decomposed in proportion to its di- 
stance from the protecting influence. 
“ The action of the salt water upon iron at this port is exceedingly 
great, causing a very rapid corrosion; work similar to what has been 
described, but in which no brass has been used, having been taken up 
as useless after a service of only eight years; the cast-iron becoming 
so decomposed as to yield easily, like plumbago, to the penknife, and 
the wrought iron wasting away to a mere thread; much, however, in 
both cases depending upon the quality of the iron. 
“ The hint thus fortunately received has, therefore, since been taken 
advantage of, and acted upon as much as possible by my father in all 
our recent works. The dock-gates, which, heretofore, have been 
greatly affected, are now in a great measure protected by using brass 
with zron whenever it can properly be done. Copper fastenings are 
no longer used, tron bolts with brass nuts and washers having been 
substituted: the sills, which are made of cast iron, have numerous 
small holes bored through them, which are again filled up with melted 
brass ; the chain-hole rollers, also of cast iron, are keyed on to metallic 
shafts, turning in cast-iron steps, and in all cases where strength and 
durability are most required, the iron in these parts is thus protected. 
So far as five years’ experience can testify, perfect success has been the 
result. The wrought-iron bolts are now as perfect as when first put 
and the cast iron shows no symptoms of decay. A proof of this 
may be seen at the outer gates of the Brunswick Basin, which were 
fastened and finished as described, and have been now in use upwards 
of five years.” 
On Browning Gun Barrels. By W. Ertrick. 
On a Method of Facilitating the Calculations of Gases. 
By Dr. CLARKE. 
On some Singular Modifications of the Ordinary Action of Nitric Acid 
g on certain Metals. By Dr. ANDREWS. 
