TRANSACTIONS OF THE SECTIONS. 83 



2. That if tlie temperature fall to 40° Fahr. and under, tlie modified seven- 

 watered salt is formed at the bottom of the solution just as in covered vessels. 



3. That if the exposed solution suddenly crystallize into a compact mass of 

 needles, a nucleus may always be found in the form of an insect, a speck of soot, a 

 black point of carbon, &c. 



4. That if during the exposure rain come on, the solution generally crystallizes 

 suddenly in consequence of an active nucleus being brought down : but if the 

 flask be put out during heavy rain, when we may suppose all the solid nuclei to 

 be brought down, the rain-drops, now quite clean, fall into the solution without 

 any nuclear action. 



6. That the young and newly sprouted leaves of trees, such as those of the 

 gooseberry and currant, have no nuclear action. 



C. That in clear cloudless weather, when the force of evaporation is strong, the 

 solutions b}^ exposure produce fine groups of crystals of the ten-atom salt, j ust as a 

 saturated solution would do if left to evaporate slowly in an open dish. 



7. That if the solution, after being exposed to the open air, be brought into a room, 

 it crystallizes immediately under the action of aerial miclei. 



On the Constitution of Salts. By J. A. "Wankltn, F.C.S. 



Recent Progress in Cheynistry in tlie United States. By C. Gilbert Wheeler. 



On the Oxidation products of tlie Essential Oil of Oranye-peel, Jcnown as 



" Essence de Portugal.'" By C. R. A. "Wrigiit, D.Sc, Lectwer on Chemistry 



in St. Mary's Hospital Medical School, and Charles H. Piesse, Assistant 



Analyst in St. Thomas's Hospital. 



Through the kindness of Messrs. Piesse and Lubin, we have had the oppoiiimity 

 of examining a specimen of pure oil of orange-peel. As stated by Soubeiran and 

 Capitaine, and also by Dr. Gladstone, this oil consists mainly of a hydrocarbon of 

 formula C,„ IIj^, boiling at 174° C, .and termed Hesperidene. We find that the crude 

 oil commences to boil at 175°, and that 97-2 per cent, comes over below 179° ; on 

 redistillation over sodium this portion all comes over between 175° and 177° 

 (uncorrected). The remaining 2-8 per cent, is a soft resin, which does not harden 

 on standing, and is perfectly fluid at 100°. It is not volatile without decomposition, 

 and after complete volatilization of residual hesperidene is inodorous ; in alcohol, 

 even boiling, it is but sparingly soluble, readily soluble in ether, and insoluble in 

 water, to which, however, it commimicates the aromatic bitter taste of orange-peel. 

 It contains no nitrogen, and on combustion gives numbers agreeing with the 

 formula Cj^HjuOg. 



Hesperidene redistilled over sodium is attacked with violence by concentrated 

 warm nitric acid ; by dilution of the acid vidth its own bullv of water the action 

 becomes less violent ; after boiling some hours with an inverted condenser attached, 

 the evolution of red fumes and of CO^ almost ceases. At this stage the hydro- 

 carbon has principally formed a brown resinous substance, becoming a very thick 

 viscid liquid at 100°, "but setting on coohng to a hard brittle mass. This contains 

 much nitrogen and less hydrogen in proportion to the carbon than the original 

 substance. Its examination is not yet completed, but the numbers obtained are 

 consistent with the supposition that it is derived from the original hydi-ocarbon by 

 addition of oxygen and replacement of hydrogen by NO^. 



With .strong nitric acid this brown resin is fui-ther acted on, producing a yellow 

 resin not softening at 100°, and containing nitrogen and less carbon and hydrogen 

 than the brown resin. Much oxalic acid is also produced, and probably also 

 another acid containing nitrogen ; for the snow-white oxalic acid got by precipita- 

 tion as lead-salt, decomposition withhydric sulphide, and several recrystpllizations 

 from water, contained much nitrogen, and yielded (as well as its silver salt) 

 numbers not agreeing with but approximating to those required by theory. 



On heating one part of hesperidene with a mixture of three parts potassium 



6* 



