S52 ANNUAL REGISTER, 1794. 



the method which appears to me to 

 succeed the best is, to cut a bottle 

 ciiculaily in a spiral slip of a few 

 lines in breadth. It is very easy to 

 cut a bottle in snch manner as to 

 form a single long slip, and tlius un- 

 necessary joinings are avoided. 



The whole slip is to be plunged 

 into ether, until it is sufficiently 

 softened, which comes to pass sooner 

 or later, according to the qualify of 

 the vitriolic ether that is employed. 

 Half an hour frequently suffices ; 

 but I have already observed, that 

 there is a great diversity in the man- 

 ner hi which different sorts of vi- 

 triolic elher act, and of which the 

 cause is not yet, so far as I know, 

 determined. 



The slip being taken out, one of 

 the extremities is to be taken hold 

 of and rolled, first upon itself at the 

 bottom of tlie tube, pressing it ; 

 then the rolling is to be conlinued, 

 mounting spirally along the mould, 

 and taking ca*^ to lay over and 

 compress w ith the hand every edge, 

 otie against the other, so jhat there 

 may not be any vacant space, and 

 that all the edges may join exactly. 

 The whole is then to be bound hard 

 with a tape of an inch in width, 

 taking care to turn it the same 

 way with the slip of elastic gum. 

 The tape is to be tied over with 

 packthread, so that by every turn 

 of the packthread joining another 

 an equal pressure is given to every 

 part : it is then left to dry, and the 

 tube is made. 



The bandage is to be taken off 

 "t;<'ith great care, that none of the 

 outward surface, which may have 

 been lodged within the hollows of 

 the tape (of which the caoutchouc 

 takes the exact impression) may be 

 pulled away. 1 advise the applica- 

 tion of a tape before tlie packthread. 



because, especially in the thinner 

 tubes, we should run the risk of 

 cutting the caoutchouc, if the pack- 

 thread were applied immediately 

 upon it 



It is easy to take off the tube of 

 elastic gum which has been formed 

 upon a solid mould of one piece ; 

 if the mould be made rather conic, 

 it may be made to slide off by the 

 smaller end : at the worst, it is 

 easily accomplished by plunging it 

 into hot water, for it is softened by 

 the heat, and is distended ; without 

 this precaution it would be some- 

 times difficult to draw it off when 

 dry, because, having been applied 

 upon the mould whilst it had its vo- 

 lume augmented by the interposi- 

 tion of the ether, the parts ot the 

 caoutchouc are drawn nearer each 

 other by the evaporation of the in- 

 terposed body. 



The great affinity between these 

 two bodies is seen by the length of 

 time that the odour of the ether re- 

 mains, notwithstanding the great 

 volatility of the latter, and that the 

 apparent dry ness of t he tube seem s to 

 shew that there is none remaining ; 

 nevertheless, after a certain tluje, 

 the odour dissappears intirely. One 

 of those tubes which are now before 

 you, and which was made with 

 ether, after tlie method here de- 

 scribed, does not retain the least 

 trace of the solvent. It is needless 

 to say, that it is easy to make tubes 

 as thin, or as thick, as may be 

 judged proper. 



Although the process that I am 

 now desci ibing i,s but very little 

 expensive, yet I have tried to em- 

 ploy other solvents in lieu of ether, 

 because it is not to be had in every 

 place, and requires a particular care 

 in its preservation. 1 have employ- 

 ed, with some success, the essen- 

 tial 



