of Carbon and Hydrogen, S;c. 133 



many of them became turbid, probably from the presence of 

 water; one, received at 176° (by which is meant that that was 

 the boiling point of the contents of the retort when it came 

 over), became partly solid, crystals forming round the side, 

 and a fluid remaining in the centre ; whilst two other portions' 

 one received at 186° and the other at 190°, became quite 

 hard. A cold glass rod being introduced into one of these 

 tubes, the mass within was found to resist considerable pres- 

 sure; but by breaking it-down, a solid part was thrust to the 

 bottom of the tube, whilst a fluid remained above : the fluid 

 was poured off", and in this way the solid portion partly puri- 

 fied. The contents of the tube were then allowed to fuse, 

 were introduced into a larger and stronger tube, furnished 

 with another which entered loosely within it, both being closed 

 of course at the lower end ; then again lowering the tempera- 

 ture of the whole to 0°, bibulous paper was introduced, and 

 pressed on to the surface of the solid substance in the large 

 tube by the end of the smaller one. In this way much fluid 

 was removed by successive portions of paper, and a solid sub- 

 stance remained, which did not become fluid until raised to 

 28° or 29°. To complete the separation of the permanently 

 fluid part, the substance was allowed to melt, then cast into a 

 cake in a tin-foil mould, and pressed between many folds of 

 bibulous paper in a Bramah's press, care having been taken 

 to cool the paper, tin-foil, flannel, boards, and other thino-s 

 used, as near to 0° as possible, to prevent solution of the sohd 

 substance m the fluid part to be removed. It was ultirtiately 

 distilled from ofi" caustic lime, to separate any water it min;ht 

 contain. ° 



The general process, which appears to me to be the best 

 for the preparation of this substance only, is to distil a por- 

 tion of the fluid deposited during the condensation of oil gas, 

 to set aside the product obtained before the temperature rises 

 to 1 70°, to collect that which comes over by 1 80°, ao-ain se- 

 parately that which comes over by 190°, and also the^portion 

 up to 200° or 210°. That before 170° will upon re-distillation 

 yield portions to be added to those of 180° and 190°; and the 

 part obtained from 190° upwards will also, when re-distilled, 

 yield quantities boiling over at 180°, 190°, &c. Havino' then 

 these three portions obtained at 180°, 190°, and 200°, let them 

 be rectified one after the other, and the products between 1 75° 

 and 195° received in three or four parts at successive tempe- 

 ratures. Then proceed with these as before described. 



It will sometimes liappen, when the proportion of bi-car- 

 buret of hydrogen is small in the lifjuid, that the rectifications 

 must be many times repeated before the fluids at 185° and 



190° 



