ON EVAPORATION AND DISSOCIATION. 
333 
3. Comparison of physical properties with those found by most careful observers, 
a. Boiling-point. Determined by numerous observers with most discordant results. 
X 
Pierre . 
66-3° 
at 759 
(at 0° ?) — Sp. gr. reduced to 0° 
0-8207 
X 
Mgndeleeff . 
66-0° 
? 
• • n 
0-8206 
X 
Kopp . 
64-9° 
at 744 
? 
0-8180 
X 
Delffs . 
60-5° 
at 748 
? 
0-8138 
X 
Dumas and Peligot . 
66-5° 
at 761 
P 
• 55 
0-8155 
X 
Detille. 
. . 
• • 55 
0-8153 
X 
Kopp (1845) . . . 
65-0° 
at 752 
• • 55 
0-8147 
X 
Kopp (1855) . . . 
64-6-65-2° 
at 744 
* * 95 
0-8142 
X 
Landolt . 
66-0° 
at 753 
• * 55 
0-8137 
X 
Duclaux .... 
66-0° 
? 
. . ,, 
0-8128 
BaO 
Grodzki and Kramer 
65-75-66-25° 
? 
(uncor.) ,, 
0-8130 
Na 
„ ,, 65-6-66-2° at 764"8 (uncor.) „ 
(Specially remarked that Na is preferable to BaO.) 
0-8116 
X 
Graham . 
66-0° 
? 
* * 55 
0-8105 
: 2 co 3 
Linnemann .... 
67*1° 
? 
• ’ 55 
ru° . . . 
0-8768 
0-79658 
uS0 4 
Perkin. 
65-8-66° 
? 760 
s 
) 2 50 
k 4, ... 
0-78714 
CaO 
Regnault . . . . 
? 
Thermometer varied at same pressure within 
several degrees. Calculated 66*78°. 
Na Schiff (once) . . . 
64-8° 
at 763. 
It is almost certain that every one of these observers has dried the sample of 
alcohol used over lime. Those marked with a X used either lime or gave no account 
of the method of drying, or we have not been able to verify the reference in Bristol. 
Grodzki and Kramer specially state that sodium is preferable to barium oxide. 
Their results are close to ours (65*6 to 66*2 at 764*8 mms., not corrected to 0 C , with 
the stem of their thermometer in vapour up to 30°). 
Schiff distilled once over sodium, and obtained a number practically identical with 
ours (64*8 at 763 mms.). 
The other results are all higher ; that of Delffs is probably a misprint. (Perhaps 
not: see Kopp.) 
b. Specific gravity. As Dr. Perkin has recently determined the specific gravity of 
methyl-alcohol, taking all precautions, and as the same method has been followed by 
ourselves, it is striking that the agreement is absolute. 
Perkin. 2 2 4 o -- — 0*78908 (calculated). 
Bams ay and Young ... ,, = 0*78909. 
Such a close coincidence, however, must be regarded as accidental. 
It is specially to be noticed that Regnault did not obtain coincident results by the 
statical and dynamical methods. He says (vol. 26, p. 461): “La courbe graphique 
que j’ai tracee sur la planche Y, d’apres les elements de cette Table, represente 
parfaitement les observations de la Serie 1, et cedes de la Serie 3, qui depassent 100°. 
