|13.  Partly CLear| 1.8378 | 1.4257 | ... | 60 | 1 | 40 | |14.  Cloudy | 1.837 | 1.4257 | 1 | 56 | 4 | 40 | |________________|____________|________|______|________|____
__|________| | | | | | |Temp., Deg.  C. | Percentage | | |_______________|___________________| | | | | | | | | From | To | Increase. | Loss. | |________________|_______|_______|___________|_______| | | | | | | | 1.  Clear | 57 deg. | 62 deg. | 31 | ... | | 2. " | 60 deg. | 62 deg. | 18 | ... | | 3.  Cloudy | 60 deg. | 62 deg. | 7 | ... | | 4.  Rain | 60 deg. | 63 deg. | 0 | 0 | | 5.  Clear | 58 deg. | 62 deg. | 15 | ... | | 6.  Rainy | 58 deg. | 62 deg. | ... | 2 | | 7.  Cloudy | 62 deg. | 65 deg. | ... | 10 | | 8.  Clear | 60 deg. | 62 deg. | 5 | ... | | 9.  Partly Clear| 50 deg. | 60 deg. | ... | 3 | |10. " | 58 deg. | 60 deg. | ... | 10 | |11.  Cloudy | 58 deg. | 60 deg. | 8 | ... | |12.  Rainy | 58 deg. | 60 deg. | ... | 10 | |13.  Partly CLear| 50 deg. | 58 deg. | 20 | ... | |14.  Cloudy | 50 deg. | 60 deg. | 16 | ... | |________________|_______|_______|___________|_______|

The lesson this table teaches is, that it is almost impossible to nitrate cellulose in small quantities, and get uniform results, when the nitration is carried on at high temperatures.  As regards the solubility of pyroxyline, Parks found that nitro-benzene, aniline, glacial acetic acid, and camphor, dissolved in the more volatile solvents methyl-alcohol and alcohol-ether, were much the best solvents for producing a plastic, as they are less volatile, and develop greater solvent action under the influence of heat.  Nitro-benzene gives a solution that is granular; it seems to merely convert the pyroxyline, and not to dissolve it; but on the addition of alcohol, a solution is at once obtained, and the granular appearance disappears, and the solution becomes homogeneous.  The acid mixture and the method of nitrating have much to do with the action of the various solvents, so also has the presence of water.

Dr Schupphaus found that propyl and isobutyl alcohols with camphor were active solvents, and the ketones, palmitone, and stearone in alcohol solution, also alpha- and beta-naphthol, with alcohol and anthraquinone (diphenylene diketone) in alcoholic solution, and also iso-valeric aldehyde and its derivatives, amyliden-dimethyl and amyliden-diethyl ethers.

August Sayer (U.S.P., No. 470,451) finds diethyl-ketone, dibutyl-ketone, di-pentyl-ketone, and the mixed ketones,[A] methyl-ethyl, methyl-propyl, methyl-butyl, methyl-amyl, and ethyl-butyl ketones are active solvents of pyroxyline; and Paget finds that although methyl-amyl oxide is a solvent, that ethyl-amyl oxide is not.