HISTORICAL SKETCH OF CHEMISTRY OF RUBBER 5 



flexible and soft, and then put round a glass rod or other 

 cylindrical body, rather smaller than the intended tube ; the 

 projecting edges are to be pinched together, and when they 

 have slightly adhered, cut through with a pair of sharp scissors ; 

 this will . . . leave the two edges slightly adhering together. 

 The junction is to be completed by immediately bringing these 

 edges into contact throughout the whole extent of the cut 

 surface ... by applying a thumb-nail. When firmly pressed 

 together whilst warm, the adhesion is such that the tube will 

 tear elsewhere as readily as at the junction. . . . They are 

 frequently useful of a conical form." A patent for an apparatus 

 for squirting gutta-percha or other plastic material through 

 an annular opening for the purpose of making continuous 

 tubing was granted to Hunt in 1850. Soon after rubber 

 tubing appears to have been adopted for chemical purposes, 

 though this was probably made from cut sheet. The first 

 reference to such use occurs in Abel and Bloxam's Hand- 

 book of Chemistry, 1854 : " Small pieces of vulcanised Indian 

 rubber tubing, which is now made of almost any dimensions, 

 answer the purpose of these connectors exceedingly well ; they 

 may not adhere to the glass quite so tightly, a defect which 

 may, however, be remedied by tying them firmly upon the 

 tubes at each extremity." But the old form was not easily 

 superseded, and in 1857 we nn d in Greville Williams's Hand- 

 book of Chemical Manipulation : " Vulcanised India-rubber 

 tubes . . . are in almost every case preferable to those made 

 in the laboratory from sheet caoutchouc ; but those which 

 are used to connect the chloride of calcium tube with the 

 potash bulbs in organic analysis are much better of the 

 latter kind. The reason is that the vulcanised ones are less 

 adhesive." 



In 1844 Hancock patented a process for moulding stoppers 

 of gutta-percha, or gutta-percha and caoutchouc. But rubber 

 stoppers for chemical purposes do not seem to have come 

 into use until about 1 865 . The introduction may be attributed 

 to Sir William Perkin. Mr. Tutin relates, on personal authority, 

 that, impressed with the unsuitability of ordinary corks for 

 organic analysis, Sir William was walking one day in London, 

 when he happened to see a block of rubber in a shop window. 

 The idea occurred to him of cutting stoppers of rubber, and 

 was put into execution forthwith. A reference to their use 



