434 
Proceedings of the Koyal Society of Edinburgh. [Sess. 
capillary, or the mark to which the bath-liquid ascends, as the case may 
be, is required. The immersed depth is measured ± 2 mm. and, taking into 
account the specific gravity * of the bath-liquid at the temperature concerned, 
is converted into mercury-height and added to the barometric reading. 
The correction for the additional pressure caused by capillary ascension 
in the tube is usually of the order of 1 mm., and will be employed only 
when the temperature is determined more exactly than ± 1/25°. 
The following are boiling-points of the same sample as obtained with 
the distilling flask (col. 7) and with the submerged bulblet (col. 6). For 
comparison, the latter boiling-points are reduced to the existing atmospheric 
pressure by the data in col. 5. The examples illustrate different miscible 
and chemically active pairs of substances and bath-liquids. The values for 
calomel and ammonium carbonate (col. 7) are taken from known vapour- 
pressure data. 
Substance. 
Bath-liquid. 
Immersed 
Depth. 
Density 
of Bath- 
liquid. 
Y.P. In- 
crease 
for 1°. 
B.P. 
Subm. 
Bulblet. 
B.P. Dist. 
Flask. 
Benzene . 
Water . 
113 
0*97 
24 
79*01° 
79*00° 
H 2 S0 4 . . 
104 
1*77 
79*04 
79*00 
5? 
Min. oil 
60 
0*9 
79*35 1 
79*33 1 
Ether 
CaCl 2 sol. 
70 
1*47 
27 
33*87 
33*85 
Water . 
73 
0*99 
33*91 
33*85 
Alcohol . 
60 
0*97 
31 
77*56 
77*55 
Camphor 
Paraffin 
45 
0*69 
20 
208*00 
207*65 
Naphthalene . 
2 nitrates 
68 
1*93 
17 
217*68 
217*73 
Calomel . 
2 „ 
59 
1*85 
383*2 
[382*5] 
Coml. am. \ 
carbonate f 
l 
Olive oil 
57 
0*88 
58*5 
[58*5] 
1 These observations were made at a different barometric pressure from the pre- 
ceding ones. 
Characteristics of the Submerged Bulblet Method . — The chief features 
of the method are : — 
(1) That it is applicable to non-fusing solids, for the determination of 
the boiling-points of which no simple and accurate method has been known. 
(2) That a minimum of material (at most OT g.) and a minimum of 
time are consumed. 
* We are indebted to Mr F. B. Plummer for making a series of determinations of the 
specific gravities of the bath-liquids at various temperatures. The following formulae 
summarise the results, and give values correct to the second decimal place within the 
limits of temperature specified : — 
Sulphuric acid (92*75 per cent., 30-200°), l*818-0*000906(t-30). 
Paraffin (m.-p. 53°, 60-230°), 0*778-0*0006 12(t-60). 
Two nitrates (230-390°), l*968-0*00075(<-230). 
