226 



JOUBNAL, R.A.S; (CEYLON). 



[Vol. IX. 



anything even resembling the real mineral. Most of that which is 

 sold to the stove-plate and other smooth-casting foundries for 

 'black lead/ is innocent ground slate, but some of it is a mixture 

 of ground coal and German black lead, while charcoal would be 

 better than either if ground fine enough. Ceylon plumbago 

 combines the two qualities of a substance almost as refractory as 

 asbestos, and the most perfect conductor of heat. These are the 

 essentials of a perfect 4 facing.' It cannot be pretended that any 

 other substance will answer as well, unless it will combine and 

 form a flux upon the surface of the metal. As for the mechanical 

 operation of filling np the pores, or smoothing the mould, plum- 

 bago has no equal. For iron castings it need not be a perfectly 

 pure article, but that it be pulverized very fine is absolutely 

 necessary for economical work and the best results." 



We now come to some miscellaneous and curious uses to 

 which plumbago is put, the mineral being applied to articles 

 so different as musical instruments, hats and boots, bottles, 

 paint, boats and yachts, Listen : — 



"For pianos, plumbago is employed to coat the bridge over 

 which the wires are drawn, because of its perfect lubrication ; it 

 prevents the wire from adhering to the wood, and should be as 

 free from impurity as that used by the electrotyper, but need not 

 be pulverized as finely. For organs, it is used to lubricate the 

 sides, and should be the same as that used by piano-makers. 

 The German black lead imparts a peculiar tone to the colours 

 and a softness and smoothness to the touch of felt hats. The 

 very best lump only should be accepted. As it has once been 

 washed and dried in lumps, they will readily separate again in 

 water, and no pulverizing is needed. For colouring dark glass 

 for carboys, bottles, &c, the best German black lead is used in 

 lumps, but no inferior grade will answer. For paint, plumbago 

 has long been known as possessing great value. The elements 

 do not exhaust it, water sheds from it as from oil itself, and fire 

 does not affect it. The grade need not be the highest. For the 

 bottoms of boats and yachts it has long been used, especially for 

 racing boats ; but only the best Ceylon plumbago, very finely 

 pulverized, is valuable." 



A substance which used, as a paint, resists the action of 

 the atmosphere and is both waterproof and fireproof, is 

 surely of great economic value, and ought to be specially 

 useful as paint for the numerous tea factories erected or 

 in course of erection in Ceylon, 



