August 1, 1864.] THE TECHNOLOGIST. 



NATAL FIBR3S. 25 



and Dr. Phipson has recently published a method of distinguishing this 

 vegetable ivory from the animal one by means of sulphuric acid, which 

 gives a beautiful purple colour with the vegetable ivory, but none with 

 the animal ivory. 



Horn. — Horns of the best quality, and especially the beautiful ones 

 obtained from the buffaloes in India and America, receive a great variety 

 of applications at the present day, owing to their toughness and elasti- 

 city, as well as to their remarkable property of softening under heat, of 

 welding, and of being moulded into various forms under pressure. To 

 apply horns to manufactures they are treated as follows : They are first 

 thrown into water, and slight putrefaction commences, by which am- 

 monia is produced, when the horn begins to soften. To carry this 

 action further the horns are transferred into a slightly acid bath, com- 

 posed of nitric »nd acetic acids, with a small quantity of various salts. 

 When the horns are sufficiently softened, which requires about two 

 weeks, they are cleaned and split into two parts by means of a circular 

 saw, and these are introduced between heated plates, and the whole sub- 

 jected to an intense pressure of several tons to the square inch. The 

 plates may be moulds, and thus the horn may be compressed into any 

 required shape. A great improvement has recently been effected in this 

 branch of manufacture, which consists in dyeing the horn various 

 colours. To accomplish this the horn is first dipped into a bath, con- 

 taining a weak solution of salts of lead or mercury, and when the horns 

 have been thus impregnated with metallic salts, a solution of hydro- 

 sulphate of ammonia is rubbed on them, when a black or brown dye is 

 produced. Another method consists in mordanting the horn with a 

 salt of iron, and dipping it in a solution of logwood. Of late, very beau- 

 tiful white fancy articles have been produced from horn by dipping it 

 first into a salt of lead, and then into hydrochloric acid, when white 

 chloride of lead is fixed in the interstices of the horn, which then simply 

 requires polishing. 



This lecture, as well as those which followed, were illustrated by 

 numerous specimens and experiments. 



NATAL FIBRES. 



In a late number you call attention to Fibre Staples, and justly re- 

 mark that they ought to take a high place amongst the future exports of 

 the colony. A short notice, therefore, of the nature and peculiarities of 

 a few of the fibrous plants indigenous to or introduced into Natal may be 

 of interest to some of your readers, and perhaps may lead some of them 

 to bring others into notice which may have escaped my own observa- 

 tion. If so, I am sure you will gladly aid us in our endeavours to gain 



vol. v. 13 



