18 MR. WATSON SMITH ON ISODINAPHTHYL. 



(b), the latter was heated up somewhat strongly, so as not 

 to allow the solidification of the naphthalin. The distil- 

 late, when it commenced to run down the bend to the cool 

 part of the tube in the retort, was worked over for a minute 

 or two as briskly as possible ; or it would certainly have 

 stopped up that cool part of the tube which dipped below 

 the stopper of the retort, causing a dangerous explosion 

 from the little flask (a). 



When the naphthalin began to run fluid into the retort, 

 the distillation was kept up briskly for a time, all solidified 

 particles being speedily remelted by the hot stream, and 

 carried before it into the retort. All danger of stopping 

 up then ceased, as the whole apparatus was too hot to per- 

 mit solidification in any part thereof. 



The substance distilling over was of a deep brown-red 

 colour, and had acquired a peculiar odour, in addition to 

 that usual in naphthalin. The gaseous product obtained 

 was just sufficient in the first trial to fill the gas -jar 

 (340 cub. cent.) . The distillation was carried on till the 

 flask was just dry, when, on removing the flame of the 

 lamp, there was always a back rush of vapour, accompanied 

 by the dropping back of a dark-looking fluid, amounting 

 in this (the first) distillation to about 1 cub. cent. 



This small quantity of dark-looking substance which had 

 dropped back out of the hot tube, was poured out into a 

 small capsule, and carefully preserved, as the first con- 

 tribution towards a quantity of the crude substance. 



What distilled over into the retort (c), of reddish-brown 

 colour, was now fused, and poured back again into the 

 little distillation-flask (a) } from which it was again dis- 

 tilled through the red-hot tube as before, in the first ex- 

 periment. It not only yielded a little freshly formed 

 substance of high boiling-point, but also left behind a 

 little which had been formed, and carried over amongst 

 the bulk of the naphthalin, in the first distillation. Thus 



