52 REPORT—1863. 
A gun-barrel was Seem filled with the first mixture and exposed to a red 
heat in a separate furnace. In the first and second series of experiments the gases 
voduced in the gun-barrel were passed through the potash-charcoal, which was 
i ¢ at a red heat in another iron tube in connexion with the gun-barrel. In the 
third series of experiments the gases were passed through hydrochloric acid; in 
the fourth series of experiments the gases were passed through the red-hot potash- 
charcoal, and then, successively, through hydrochloric acid and a solution of potash. 
In this series of experiments the gases which escaped were collected and analyzed. 
The prussiate of potash which was formed was extracted and crystallized. The 
ammonia was estimated by means of platina, and afterwards calculated into the 
equivalent of prussiate of potash. 
The theoretical yield of prussiate of potash was 382°50, and the results of the 
experiments are shown in the following Table :— 
ul 2. 3. 4, 
From the retort.........06. 101:97 135-46 146:93 141-08 
From the tube ............ 68-25 63°54 “% 71:00 
From the hydrochloric acid. . 36 140:24 58°80 
From the potash .......... ie 2°75 
Total prussiate ....= 170-22 199-00 287°17 273°63 
LB a os ae Soe sede 183-50 95°33 108:87 
Produce per cent...= 44:5 52:2 75-1 71:5 
The gases evolved in the fourth series were collected after the experiment had 
been some time in operation, and consisted of— 
iNbLIO an doe Aa Ran ooo pone feitsken 14:00 
PAP ARGC os winsaiaye'h erh.ns nis Gk» co 46-00 
Carbonic oxide ..... sno aon otaee . 25°34 
Carburetted hydrogen .......... .. 14:66 
100-00 
It therefore follows that a quantity of the nitrogen is lost in consequence of its 
being isolated; but the principal source of loss in the process arises from this 
substance escaping in the form of ammonia. 
On the Separation of Lead and Antimony. 
By Tuomas Ricwarpson, M.A., Ph.D., F.RS.E., Se. 
The hard or slag leads of commerce are softened in the following manner :— 
A quantity of the lead is melted in large shallow metal pans, and exposed to a 
current of hot air; the antimony, alloyed with a certain quantity of lead, becomes 
oxidized, and the dross which is formed floats on the surface, whence it is skimmed 
off by the workman. The lead which remains is now soft and malleable, and 
nearly free from antimony. 
When the dross is reduced to the metallic state, it may be submitted to the 
same process, when a further separation of lead takes place. The dross from the 
second calcination contains the lead and antimony in about equal proportions, 
beyond which this process of calcination cannot be carried. 
The following analyses show the changes which take place in these operations :— 
EneuisH Harp Leaps. 
Original Lead, First Calcination, Second Calcination. 
Lend: pase ese we seuss ONE 86°53 52°84 
Antimony’ 030.4 53%.5° °° O57 11:29 47:16 
Coppergocstsurrare s OTe trace trace 
From vietewsseecsss O02 0°34 trace 
100:00 98:16 100-00 
