274 DE. HEEMAXN- KOPP ON THE EELATION BET^EN BOmNO-POEST 
Table XXVII. 
Calculated. 
Observed boiling-point. 
... 
Methyl-piperidine 
104 
Cahours, 117^ 
... 
Ethyl-piperidine 
123 
Cahours, 128°. 
C2„h,,n ... 
Amyl-piperidine 
180 
Cahours, 186°. 
C,eH,,N ... 
Methyl-ethyl-amylamine 
132 
Hofmann, 135°. 
... 
Diethyl-amylamine 
151 
Hofmann, 154°. 
C30H33N ... 
Triamylamine 
265 
Hofmann, 257°. 
Accordingly in the last two series also the difference in boiling-point (19°) seems, at 
all events approximately, to correspond to the elementary difference C, H,. We meet, 
however, with an exception in the boiling-point of tiimethylamine, Cg Hq X, a base 
likewise belonging to the tertiary monamines, which, according to Wixeles, hes between 
4° and 5° *. 
The general formula C„ Hn+g N represents volatile bases of the three classes. What 
is known with regard to the boiling-points of the tertiary monamines has already been 
stated. With respect to the secondary, Hofmaxx’s deter-mination of the boiling- 
points of diethylamine, CgHnN, =57°‘5, of diamylamine, C 20 II 23 X, = about 170°, also 
exhibits for the difference of composition ^C 2 ll 2 , a difference in boiling-points of 19° 
(170 — 57 = 6x19°). The difference is greater for the primary bases the 
boiling-points assumed in the following Table are based on the suppositiorr that it 
equals 25°. 
Table XXVIII. 
Assumed. 
Observed boiling-point. 
c. 
H, N ... 
Methylamine 
O 
- 6 
Wurtz, about 0°. 
c^ 
N ... 
Ethylamine 
+ 19 
Wurtz, 19°. 1 
c„ 
h' N ... 
44 
H,,N ... 
Butvlamine 
69 
Wurtz, 69°— 70°. 
c,„ 
H„N ... 
Amylamine 
94 
Brazier and Gossleth, 93°; Wurtz, 95°. 
c„ 
H„N ... 
119 
c,^ 
H„N ... 
144 
1 
c,„ 
h!'n ... 
Caprvlamine 
169 
Squire, 164°; Cahours, 172° — 175°. j 
In the case of the bases C„ Hn +3 N, it does not appear that the isomeric terrrrs belong- 
ing to the classes of secondary and tertiary monanrines carr be distmgirished by means 
* The trimethylamine used by M. Winkles, in determining the boiling-point, had been prepared fi^om 
the brine of salted herrings. Whilst Professor Kopp’s paper ^yas passing through the press, I had an 
opportunity of determining the boiling-point of perfectly pure trimethylamine, prepared by the action of 
potassa on iodide of tetramethylammonium. This determination, made with about 10 grms. of base, gave 
the boiling-point 9°’3. The ebullition of trimethylamine exhibits the iiTegularity so frequently observed in 
methyl-compounds. When the liquid ceases to boil freely, the thermometer is observed to indicate as much 
as 14° and even 15°, but the mercury falls again suddenly to 9°'3, when ebullition recommences. It deserves 
to be noticed, that trimethylphosphine exhibits a similarly discrepant boiling-point. The boiling-poiut of 
trimethylphosphine was found between 40° and 42°, that of triethylphosphiue being 127°‘5. — A. W. H. 
