applications. Even with a 10-inch linear rule, components of highest molecular weight can be read directly to 0.5%. This corresponds to an absolute displacement of about 0.5 mm., the smallest interval between graduations on the 10L scale. Estimation to 0.25% is, therefore, possible. For most components, estimation to 0.1% is feasible.Such accuracy is possible because all possible ranges of composition need not be covered. Where all possible compositions must be allowed, the largest scale must be set equal to the full length of the rule. If the components exhibit a wide range of molecular weights, the smaller scales (representing components of high molecular weight) might be badly compressed. This difficulty can be overcome in the circular rule by choosing some intermediate scale as standard and handling by parts compositions that ,cannot be incorporated on the longer scales. It may be necessary to "overrun" the zero setting in some summations, but this presents no difficulty.

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The synthesis of 2-( 1-cyclohexenyl)cyclohexanone, together with its conjugated isomer 2-cyclohexylidenecyclohexanone, has been accomplished using anhydrides of phosphoric acid. The title compound has been separated from its conjugated isomer by lowtemperature crystallization from a hydrocarbon solvent.TThE SELF-CONDENSATION product of cyclohexanone (I) was first made by Wallach (12) in 1896. Since

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THE device is housed in a box 12 inches long x 9 inches wide x 9 inches high and, apart from the relays, is constructed from common electronic components. Although designed for use with the two-rate burette valve described earlier,' it can be readily adapted to operate syringe and other electrically-operated titrant-delivery systems.In a titration that proceeds with increasing cell e.m.f., the latter is opposed by a pre-set voltage equal to the cell e.m.f. at the desired end-point. The net voltage is applied to a relay system that responds only when the polarity is correct. The net voltage, initially of the wrong polarity, falls progressively to zero as the titration proceeds; sign reversal then causes the system to respond and to stop the titration. An analogous principle is used to stop a titration that proceeds with decreasing cell e.m.f.Results are obtained rapidly when titrant addition is comparatively fast, but the inevitable overshoot gives poor precision and accuracy.2 Rapid addition of most of the titrant is usually permissible, provided that the titration is completed a t a slower rate. This is achieved by the introduction of an auxiliary voltage that triggers the system a little before the desired end-point. This changes the flow rate of titrant from fast to slow and eliminates the effect of this auxiliary 1 Fig. 1. Circuit diagram of autotitrator (for values of components, see Appendix, p. 910)

precipitate is obtained. The analyses3 support the formula for bistrichlorostibine-triscarbonmonoxide iron, Fe( CO)r-(SbC13)*: Fe, 10.4 (calcd. 9.37); Sb, 39.3 (calcd. 40.83); C1, 34.4 (calcd. 35.70). The presence of carbon monoxide was shown qualitatively and a rough qualitative estimate of the gas evolved on thermal decomposition of the compound agrees with the other analyses. Like iron pentacarbonyl, the antimony trichloride complex is photosensitive, darkening on exposure to light, and consequently the reactions were carried out in absence of light.Both the nickel and iron complexes are amorphous powders, insoluble in organic solvents such as benzene, pentane, cyclohexane and carbon tetrachloride. Carbon disulfide reacts, liberating carbon monoxide and leaving dark colored residues. With alcohols and acetone, decomposition occurs, carbon monoxide is evolved, and solutions of divalent nickel and iron result, leaving a precipitate of antimony oxychloride. With water, dilute acids and alkalies, similar rapid reactions occur with loss of carbon monoxide, giving nickelous or ferrous solutions or hydroxides, antimony oxychloride or antimonate. The compounds are decomposed on heating to give carbon monoxide and, in the case of the iron compound, some metal carbonyl together with antimony trichloride. On treating the compounds with phosphorus trichloride, there is a vigorous reaction evolving carbon monoxide and it is possible that further substitution occurs; the color of the residue is darker but no analyses have been made.The great difference in properties between the antimony trichloride substitution compounds of nickel and those formed by the phosphorus halides may be due to the increasing inertness of the electron pair in the antimony halides compared with the phosphorus halides. Presumably there is also a lowered tendency to form T bonds with nickel which operate t o stabilize metal complexes. Efforts to identify further antimony trichloride substitution products were without success.Thanks are due to Mr. Thomas Vasilos for his assistance in part of the work, and to Professors John Kr. Irvine, Jr., and Charles D. Coryell for their valuable advice and discussions.

SUMMARY Thirty compounds in the volatile fraction of McIntosh apple juice were isolated and identified. Material for gas chromatography was prepared by concentrating volatiles tenfold in a rising film evaporator and extracting with ethyl chloride. The compounds were identified by comparing retention volumes and infrared spectra with those of known compounds. Volatile components tentatively identified on the basis of their infrared spectra and retention data included 4 aldehydes, 1 ketone, 11 alcohols, 10 esters, and 4 fatty acids. In addition, 7 peaks were found but not identified. A variety of column packings and operating conditions were necessary to obtain reasonable separation of the components isolated.