16G EFFECTS OF SULPHUR UPON IPvON FENCING. 



He had seen four fences, erected with standards the same as above, 

 rendered as thin as the blade of a pocket knife, having stood 

 respectively for ten, fourteen, sixteen, and twenty years. The 

 pillars, straining posts, etc., were reduced in like degree; also a 

 gate hung upon iron pillars, 1 f by 1 f inches, about fourteen years 

 ago, during a sharp breeze of wind one night, was laid flat upon 

 the road, pillars and all. I have sent for inspection samples of 

 iron corroded by sulphur, with a paper giving the following par- 

 ticulars : Sizes, where and when erected, by whom, practical or ama- 

 teur fencers. I need only say further that the iron is found in its 

 eai^ly stages of corrosion firmly adhering to the sulphur, and is 

 gradually reduced ; more room for expansion having thereby been 

 made, the corrosion goes on rapidly, and ultimately the iron is 

 wasted. 



Some stones more porous than others may tend either to in- 

 crease or to retard the progress of corrosion. Another matter for 

 consideration is whether the stone bedded in wet or dry soil has 

 the greatest tendency to cause corrosion, or stone deeply bedded 

 in the soil, or laid upon its surface. I would make a natural rise 

 or fall with the ground where the fence is to be erected, and leave 

 the top of the stone exposed, as the fence could be easily varnished 

 during winter or spring before the foliage grows to cover the stone, 

 or any part of the fence. Galvanised materials, however, are pre- 

 ferable, and the cost is little more ; the process, however, reduces 

 the strength of materials by about 20 per cent., as varnishing is 

 thereby rendered unnecessary. Larger stones, in some cases, might 

 require to be used if bedded upon the surface. 



Batting with lead is the best plan in either case, as it does not 

 injure the iron. I find iron which has stood for twenty years, 

 batted with lead, as clean and sound as when put in, the rule sur- 

 face of the iron never having been broken. Lead is not more 

 frequently used, because it gets loose in the stone ; the iron, heated 

 by atmospheric influences, expands, and the lead yields before it ; 

 and when it cools and contracts, a vacuum remains round the iron. 

 To prevent this, I drive in four small half oval wedges 3 inches 

 long round the straining pillars and resisting posts, the hole 4 

 inches deep, as suited to size of bore in stone, and two similar 

 wedges, 2 inches long for the standard, the holes being 3 inches 

 deep, putting the flat sides inwards, and driving them tightly on 

 the opposite sides at the same time, when the lead becomes solid 

 round the pillars, etc., at top and bottom of the hole; and this 



