382 CAOUTCHOUC, OR INDIA RUBBER. 



boiling water, and thus made into plates of the desired thickness, or into 

 various articles, which appear as if cut out of a solid block." 



Such, then, is a summary of the mode in which tortoiseshell is worked. 

 By means of heat and pressure it can be made to assume many forms, and 

 thus it becomes manageable in the hands of the workman for the diverse 

 purposes of use or luxury to which it is applied. Some of the beauty of 

 the tortoiseshell is, however, lost by the soldering process ; and that moulded 

 from the dust and raspings is of one uniform colour, without white spots. 



What is known in commerce as tortoiseshell, is strictly the thirteen 

 scales which cover the carapace. The names given to these are, two main 

 plates, two plates, three backs, two wings, two tongues, two shoulders — in 

 all, thirteen. In an animal of the ordinary size, about three feet long and 

 two and a half wide, the largest plates will weigh about nine ounces, and 

 measure about twelve inches by seven, and one-fourth of an inch thick 

 in the middle. 



CAOUTCHOUC, OR INDIA RUBBER. 



BY BENJAMIN NICK.ELLS. 



We propose, in this paper, to offer a few observations on a substance 

 which, from its importance in the industrial arts and pursuits, must 

 be classed among our most valuable productions. Caoutchouc, or, as it 

 is more familiarly termed, India rubber, applicable to a vast variety of 

 purposes directly concerned in and intimately connected with the business 

 of life, — combining qualities possessed by no other known material, and 

 capable of being procured in inexhaustible abundance, — is invested with an 

 interest of high order, second only to that associated with iron and timber. 

 Few are probably aware of the comparatively late introduction of caout- 

 chouc into this country, and it may not be uninteresting to state that Dr 

 Priestly, in the preface of his book on Perspective, printed in the year 1770, 

 says — " Since this work was printed off, I have seen a substance (no name is 

 u given to it) excellently adapted to the purpose of wiping from paper the 

 " marks of a black-lead pencil. It must therefore be of singular use to those 

 " who practise drawing. It is sold by Mr Nairne, mathematical instrument 

 "maker, opposite the Royal Exchange. He sells a cubical piece of about 

 " half an inch for three shillings : and he says it will last for several years." 



We can scarcely conceive anything more primitive than the condition 

 of caoutchouc at the time it made its first public appearance under the 

 auspices of Dr Priestly ; yet, within a few years, it has established for 

 itself an unparalleled reputation. Prior to this date however, and mainly 

 owing to the explorations of M. De la Condamine in South America, 

 caoutchouc was known as a botanical product of certain tropical climates, 

 an account of which was published by him in the ' Transactions of the 

 French Academy ' in the year 1736. Although its true source was thus 



