ON ARTIFICIAL REFRIGERATION. 937 



by the tube r/, rt, aud consequeutly it arrives in a large rectangular space 

 II, wlrich is nothing but a refrigerator. 



"Before further describing this refrigerator I will describe the use of 

 the float space G. 



"The trimethylamine is condensed at about 10°. Eunning water liav- 

 ing generally a temperature of from 10° to 28°, according to the climate 

 and seasons, a slight pressure over that of the atmosphere will be neces- 

 sary to effect its condensation, and afterwards a pressure such as that 

 already described in the condenser E. On the other hand, as cold is to 

 be produced, that is to say 12° to 15° below zero, it is necessary to have 

 a certain vacuum in the apparatus in order that the trunethylamine 

 may be vaporized. It is to allow these two phenomena to be produced 

 simultaneously that the float sx)ace G is employed, which puts a barrier 

 between the two of them. 



" The arrangement of the refrigerator allows of i^roducing cold method- 

 ically, that is to say, to cause the pm-est trimethylamine to arrive on the 

 coldest surfaces in such a manner that the energy of the vaporization 

 remains constant. 



"The refrigerator consists of a rectangular cast-iron fi-ame h «, h cr, h a, 

 li «, provided ^vith a flange on each side, which allows of tightly closing 

 it by means of two i)lates of sheet iron held by a suitable number of tie 

 pieces and nuts. Throughout its height it is furnished ^^ith a certain 

 number of tubes //, &, which are joined together at their ends by elbows 

 joining them together two and two, thus forming one continuous pipe. 



" If a current of uncongealable liquid (solution of chloride of calcium 

 or other suitable solution) be thrown into this tube at its lower part by the 

 tube <7, c, this current will rise through all the tubes, and finally egress 

 by the tube ^, d^ meanwhile the liquified current of trimethylamine 

 enters by the tube g, «; this liquid runs into the trough g e, g e, which 

 distributes it through the whole length of tubes h, li. The trimethyla- 

 mine deposited by the i)oints, with which the under side of the tubes 

 are fiu-nished, runs over the periphery of the first tube, then that of the 

 second tube, and so on for the following tubes, and constantly vaporiz- 

 ing, thereby constantly produces cold, but in so doing is impoverished, 

 for the water which it draws with it does not vaporize ; on the contrary 

 it increases the solution in i)roportion as its ad\^ances and paralyses the 

 vaporization. 



"To withdraw all that part of the trimethylamine that may vaporize 

 when this liquid arrives at the lower part of the refrigerator H, it is dis- 

 charged by the tube i a into a tabular receiver I, which is in fact a 

 vaporizer, in the tubes of which circulates the current of chloride of cal- 

 cium which has been to convey the cold, and in consequence is there at 

 its highest temperature. Under the effect of this temperature, propor- 

 tionately raised, the last possible vapours of trimethjdamiue escape; they 

 are conducted by the tube i, h into the refrigerator H, where they are 

 reunited -with those which are ah-eady formed there. But in order that 



