( 676 ) 



4'i' . an apparatus sjjj which will be described in detail in the following 

 section and intended to deliver a stream of calciumchloride solution 

 at a low but very constant temperature. 



We may consider the methylchloride vapour which streams out 

 of these refrigerators and regenerators. In the case 3 above (some- 

 times also in case 2 for which the connection ^i serves) it would 

 be sucked by a Burckhardt — Weiss vacuum pump ^!, installed in 

 the manner given in Comm. No. 83. B'rom here it would travel to 

 one of the conjugated pumps of the Société Génèvoise ^\ mentioned 

 in Comm. No. 14, which receive the vapour from the Burckhardt 

 or from all other apparatus (S PI. II and further indicated under 2). 

 This pump ^^^ may for another example take the vapour directly from 

 the boiling vessel ^ (see PI, II and L PI. I) as weW as between the 

 hio-h and low pressure cylinder from the branch tube •(?, which too 

 allows gas to be pumped from one of the four above mentioned 

 sacks •!?, in which the methylchloride can be preserved for a short 

 time and of which only one is represented on PL II, while other 

 sacks can be connected to apparatus from which methylchloride 

 escapes under constant pressure. The pump is provided with an 

 indicator on the low pressure cylinder, a vacuummeter between 

 the hio-h and low pressure cylinders and a manometer on the high 

 pressure cylinder, besides several cocks which are required for 

 pumping, drying and filling with methylchloride. The vacuum meter 

 ^mv indicates the pi-essure of the gas wiiich enters the high pressure 

 cylinder. From the cylinder volume and the number of strokes one 

 can derive the volume of gas and reduce it to that under normal 

 conditions moved in the cycle, so that the velocity with wdiich the 

 liquid in the refrigerator evaporates can be followed. 



In addition a safety valve ^w is added to the high pressure cylinder 

 principally to protect the condensor 5\ 



The methylchloride which can escape from this safety valve is 

 passed into the above mentioned sacks -0. Usually, all the methyl- 

 chloride passes into the condenser, where it is cooled by running 

 water from the main. In between, an oil trap ^- is placed which 

 is slightly warmed by steam (see Q:\-„,X so that the transported oil 

 shall give up the dissolved methylchloride. The oil thus separated 

 by the change of direction is run into a flask iv. The last portion 

 of the methylchloride, freed here, is carried to the sack •!?. At the 

 top of the oil trap, the gas is freed from the last traces of oil by 

 layers of felt and wadding contained between sheets of metal gauze. 

 (C.f. the oil trap of the ethylene circulation shown by Mathias I.e. 

 p. 383 fig. 1). 



