THE ODOUR OF ROSE. 57 
In both cases the extraction by alcohol is effected in the usual 
way (as described for rose-pommade). Another patent was taken 
out in France by Piver in 1872* for “ Improvements in processes 
for the ‘ enfleurage ’ of fatty substances.” 
In 1888 a process was patented in England by Nellenstein, a 
chemist of Amsterdam+, to extract the perfume of flowers by 
means of a vacuum and refrigeration. The flowers being placed 
in a vessel of sufficient strength to resist external atmospheric 
pressure, the air was exhausted and caused to pass through a 
vessel surrounded by a freezing-mixture, and then into a third 
* No, 95326, + Patent No, 15299. 
