56 . ODOROGRAPHIA. 
before any decay has taken place in the petals, also without 
causing any change by oxidation of the molecules of aroma during 
the process. The process must work rapidly, so as to dispose of 
a great bulk of flower at once, and so keep pace with the harvest 
during the very short time which it lasts, in fact to use up every 
day the whole of the flower which can in that day be cut. 
In 1856 an invention was patented in France by Piver* called 
a pneumatic process. ‘This consisted in spreading the flowers on 
perforated metallic plates enclosed in an air-tight chamber, and 
passing through them a current of carbonic acid gas, which was 
afterwards conducted into a vessel containing liquid grease kept 
fluid by heat; this vessel was fitted with revolving plates so as 
to continually present a fresh surface to the gas, and so absorb 
the particles of perfume with which the gas was impregnated ; 
the gas was then passed through a second vessel fitted in the 
same way, and was then forced again through the chamber con- 
taining the flowers, thus being made to circulate several times, in 
order to abstract all the particles of aroma and deposit them on 
the absorbent grease. 
Another apparatus was toute in France by Piver in 18597, 
and described by Turgan in his ‘ Grandes Usines de France,’ 1865, 
peiz9., itis deatal as follows :—The apparatus consists of 
two chambers communicating with each other at the basement, 
and fitted with moveable perforated metal trays on which the 
flowers are strewn; between these trays are plates of glass on 
which is placed the grease, not spread as a paste but in a sub- 
divided condition obtamed by forcing it through a piping press 
and cutting it into small cylinders, The air is forced to and fro 
between the two chambers by means of a bellows arrangement on 
the top of each chamber, and the plates of glass, which are a trifle 
narrower than the width of the chamber, are arranged in an alter- 
nate manner so that the current of air travels between each plate, 
as explained in the annexed illustration. The doors of the appa- 
ratus fit air-tight, and are closed during the operation, so that the 
same air constantly travels from one chamber to the other. The 
inventor of this apparatus claims that flowers can be exhausted of 
their perfume with great rapidity, and it can be absorbed either 
by finely-divided grease or by olive-oil soaked into cotton cloths. 
* Brevet 15950, + No. 41090. 
