LETTERS Frozen Stoppers
To tthe Editor: May I suggest, with regard to M. Gordon Duvall's recent description of wrenching a frozen glass stopper from a bottle by force, that he use a bit of persuasion by first wetting the towel wound around the stopper and neck with hot water or steam. As a matter of fact, I can recall hardly a stopper which has not come off meekly after simply heating the neck in a blast of steam or after dipping the stoppered end of the bottle momentarily in a beaker of boiling water. Also, one might immerse the entire bottle in hot water to cause an internal pressure helping to blow out the stopper. I have used this latter method (thanks to Professor A. A. Morton of M.I.T.) very successfully with frozen glass joints of reaction vessels by applying air pressure to the closed system while heating the frozen ioint in a luminous flame. M a y 1 alter a well-known proverb by suggesting that an ounce of persuasion is worth a pound of force. GILBERTE. MOOS
not be expected to be very electronegative), (2) the conlombic interaction of the opposite charges in Ib which tends to make the dipole unstable, and (3) the presence of the relatively unstable quinonoid arrangement in Ib compared to the stable benzenoid arrangement in Ia. There is thus a strong tendency toward the classical configuration Ia as has already been suggested by Lewis and Calvin [ C h a . Rev.,25, 308 (1939)l who, however, give no detailed analysis of the problem. The result of this marked difference in stability between Ia and Ib is that resonance is considerably suppressed which corresponds to the relatively light color (yelloworange) of the compound. On acidifying the dye, the proton is most likely to become attached as shown in I1 as originally suggested by Hantzsch [Ber., 41, 1184 (1908); 42, 2129 (1909)], and the resonance scheme 11a't-r 116 becomes possible.
51 ERKRNBRECABR AVENUE CINCINNATI. OHIO
This is resonance of a modified amidinium ion type I I
I
I
* I
'.
[> N-(C-=)a -&N+
