110 Connecting; and Coating of Iron Bars . 
NO. 2t. 
Description of a Method of connecting Iron Bars , and 
coating them with Lead, so as to form solid Pillars for 
Light Houses on Bocks covered at High Water , and 
to defend them from Corrosion . By Captain Joseph 
Brodie, of the Royal Navy * 
(With an engraving.) 
FIG. 1, Plate 4, 4 shows four rods of cast iron, com- 
posed of a number of pieces two feet long, ri vetted toge~ 
ther In a manner explained by the plate, so as to produce 
the effect of one bar of the thickness of the whole. B, a 
tube of east iron, formed from a number of separate pieces, 
each about ten inches long, and which, when placed round 
the iron rods above mentioned, and then screwed toge- 
ther, form a mould, into which the melted lead is to be 
poured, to coat the iron rods. G. A portion of the rods 
covered with the melted lead, so as to form a cylindrical 
pillar apparently of lead, the iron being perfectly coated 
therewith. 
Fig . 2. D shows the manner in which the hollow cy- 
linder is formed to any length required, by the junction of 
a number of semi- cylinders ri vetted together and fitting 
each other. E, the side flanges screwed close together. 
F, the end flanges also screwed together, as prepared for 
the melted lead. 
After a certain portion of the iron rods are coated with 
lead, the lower parts of the tube are taken off and placed 
higher up ; by which repeated changes, a few tubes will 
answer the purpose to coat any length of the iron rods. 
* Nicholson, vol. 11, p. 108. Communicated to the Society of Arts, (Memoirs, 
mdccciv. 258.) who voted him the gold medal. 
