190 E. DIVERS AXD M. OGAWA : 



made use of as the medium of the union, in order to keep the 

 temperature under control. The ether, freed from alcohol and 

 water by sodium, was contained in a small flask, fitted with 

 inlet and outlet tubes, which was to serve, not only for the pro- 

 duction of the new substance, but for its isolation and its weigh- 

 ing for analysis. The flask was put in a bath of ice and salt, 

 with the outlet-tube dipping into ;i trough of mercury, and then 

 the ether was saturated with dried ammonia. Having shut off' 

 the ammonia, a very slow current of sulphur dioxide was sent 

 into the solution while the flask was continuously shaken, not 

 only in order to diffuse the heat, but to prevent the product 

 from caking on to the bottom of the flask and shutting in ether. 

 The mouth of the tube conveying the sulphur dioxide soon 

 became filled with a yellow pasty mass (p. 102), and had to be 

 kept open by a platinum rod, manipulated through the rubber 

 tubing above, but the precipitate itself was quite white and pow- 

 dery. In spite of the external cooling, the heat of combining 

 was sufficient to cause ammonia gas, saturated with ether-vapour, 

 to escape through the mercury sealing the exit-tube, and when 

 this escape became slight, the passage of sulphur dioxide stopped. 

 With the use of about 20 c.c. ether, there had then formed well 

 over a gram of the substance. In order to secure this undecom- 

 posed, a second flask was put in connection with the preparation- 

 flask, and ammonia again passed to the saturation point. The 

 ammoniated ether was decanted off through the connecting-tube 

 into the second flask, which was then detached, the whole opera- 

 tion being carried out in the freezing- mixture. The current of 

 ammonia was renewed over the ^precipitate in the flask, and 

 continued for hours, until all the ether adhering to the precipi- 

 tate had been carried away, the flask being all the while still 



