128  ON  THE  MANUFACTURE  OF  OLEUM  JETHEREUM. 
for  some  time,  with  a  view  of  ascertaining  at  what  temperature 
the  yield  of  heavy  oil  of  wine  was  most  abundant,  and  also  to 
decide  whether  the  troublesome  frothing  could  be  regulated, 
and  how  far  it  was  influenced  by  the  temperature. 
The  following  table  is  compiled  from  a  series  of  observations 
as  to  temperature,  collected  during  a  period  of  three  months, 
and  represents  a  fair  average  of  results  ;* 
'd 
O  3 
M 
<v  a 
O 
<D  O 
o 
©  o 
M 
o 
<d  o 
M 
<v  o 
M 
o  O 
'2  ° 
p  ]3 
*° 
U  o 
g  o 
Number. 
Amount 
Temperal 
at  9  o'( 
Temperal 
at  10  o 
Temperal 
at  11  o 
Temperal 
at  12  o 
Temperal 
at  1  o'( 
Temperat 
at  2  o'c 
Temperal 
at  3  o'c 
i  Temperat 
at  4  o'c 
Yield. 
Galls. 
O  p 
O  Jj^ 
o  p. 
O  J? 
o 
o  p. 
o  jr. 
o  p. 
oz. 
1 
287 
290 
*307 
298 
284 
289 
*304 
276 
2 
H 
160 
261 
*303 
*307 
*313 
297 
282 
3 
178 
*307 
*306 
*306 
*302 
297 
*306 
298 
4 
174 
298 
*307 
*306 
*307 
291 
*316 
*304 
5 
190 
289 
*313 
4| 
6 
164 
299 
*310 
*306 
H 
7 
H- 
198 
*310 
*305 
*314 
293 
*306 
294 
275 
H 
8 
116 
276 
298 
*300 
*304 
296 
*309 
293 
9 
H 
150 
230 
289 
*301 
292 
288 
*300 
296 
H 
10 
148 
23? 
288 
*302 
293 
298 
293 
*306 
31 
11 
H 
156 
295 
*308 
*303 
296 
*307 
*303 
290 
H 
12 
108 
276 
*302 
298 
*300 
299 
290 
294 
H 
13 
H 
128 
*300 
296 
287 
288 
207 
251 
4 
In  case  of  No.  5,  the  liquid  frothed  and  boiled  over  between  11  and  12 
o'clock.    Iu  that  of  No.  6,  it  boiled  over  between  1  and  2  o'clock. 
It  will  be  observed  from  the  above  table,  that  the  results 
were  very  variable ;  yet  they  indicated  that  the  quicker  the 
temperature  is  brought  to  300°  F.,  and  the  longer  it  is  kept 
above  that  point,  the  larger  will  be  the  yield.  Nos.  3,  2  and  4 
will  fully  explain  the  advantage  of  heating  quickly  and  keep- 
ing up  the  temperature,  while  the  numbers  from  9  to  13  will 
show  the  disadvantage  of  a  low  temperature.  Number  1  is  the 
only  instance  that  came  to  notice  in  which  a  low  temperature 
gave  a  good  yield. 
As  regards  the  frothing,  no  very  satisfactory  conclusions 
*  In  this  and  the  following  table  all  temperatures  of  300  and  above  are 
marked  *. 
