ee ee ae ee pawl k meee 
Notes oN ‘SCIENTIFIC RESEARCH. Tips ae 95 
is of more Re renance than a positive one. 
~The Prussian blue reaction is specific to hydrogen cyanide and must be carried 
out with each test. 
E The same applies to the sulphocyanate reaction; some parts of the ee however, 
2 “contain sulphocyanates, so that hydrogen sulphocyanate may pass over into the distillate, 
_ which then must be tested for by ferric chloride. In case of a positive reaction the 
hydrogen cyanide must be redistilled from a borax eae. 
_ As to the determination of the cinnamic acid content in storax, vide p. 66. 
a 
+ 
v 
Physical Notes. 
C. Harries and R. Haarmann‘) describe a laboratory-scale apparatus tor steam ~ 
- distilling in vacuo. They make use of steam of 3 to 4 atmospheres pressure and con- 
"duct it through a round-bottomed flask acting as receiver for the condensed water and 
then through a reducing valve to a superheater. Between the latter and the flask 
serving as receptacle for the substance, a thermometer. is inserted for measuring the 
temperature of the superheated steam. The flask is equipped with a head filled with 
“glass tubing in order to avoid foaming and carrying over of drops during distillation 
and mounted with a thermometer for reading off the temperature of the liquid distilling. 
The long condenser is followed by a worm condenser leading to the receiver. 
3 An efficient apparatus for fractional distillation under diminished pressure has been 
devised by W. A. Noyes and G. S. Skinner’). It consists of a 50 cc. bulb with rather 
‘narrow neck, probably for inserting a capillary tube or adding splinters of porous tile. 
On the one side of the flask there is arranged a separatory funnel of 50 cc. with glass 
stopcock, on the other side a high fractionating column with a great number of inden- 
tations distributed regularly on the stem. The funnel with eee offers the advantage 
+ of refilling the bulb without losing the vacuum. 
2 E. Hildt*) has constructed a new apparatus for fractionating petroleum and other 
volatile liquids. It comprises six fractionating flasks connected with each other which 
may be heated separately and bear a contrivance enabling automatical syphoning of 
_the fractions. We refer to the description of the design in the original paper, where 
_ also an illustration of the rather complicated apparatus is given. 
On page 114 of our last Report we dealt with a paper of H. Zwaardemaker*) on 
the phenomena of electric charging when odoriferous bodies are sprayed. Since that 
time, a paper on this subject has appeared from the pen of E. L. Backman®) from 
which it appears that Zwaardemaker’s “spray electricity” is to be of a different nature 
from the ordinary “cascade electricity”. The action of salts on electricity produced 
| Spraying aqueous solutions of volatile bodies is opposite to their influence on 
“cascade electricity”. Probably, volatilisation plays an important part in the origin 
a 1) Berl. Berichte 51 (1918), 788. — *) Journ. Amer. chem. Soc. 39 (1917), 2718. — #%) Compt. read. 
165 (1917), 790. — *) koninkl. Akad. van Wetenschappen te Amsterdam 24 (1916), 1630; 25 (1916), 3, 512. — 
s Phiiger’s Arch. d. Physiol. 168 (1917), 351; Chem. Zentralbl. 1917, Il. 753. 
