Now, since cohesion tends to produce solidification, we should in the first case expect to find the melting-point of the mixture higher than the mean of the melting-points of its constituents, or the curve of melting-points would be of the form given in a, Fig. 3. Here no eutectic mixture is possible.
[Illustration: FIG. 3.]
In the second case, where cohesion A B = cohesion A + B, we should obtain melting-points for the mixture which would agree with the mean of the melting-points of the constituents, the curve of melting-points would be a straight line, and again no eutectic mixture would be possible.
In the third case, however, where cohesion A B is less than cohesion A + B, we should find the melting-points of the mixture lower than the mean of the melting-points of its constituents, and the curve of melting-points would be of the form given in e, Fig. 3. Here, in those cases where the difference of cohesion on mixture is considerable, the curve of melting-points may dip below the line e f. This is the only case in which a eutectic mixture is possible, and it is, of course, found at the lowest point of the curve.
If it be true, as above suggested, that the force of cohesion is at its minimum in the eutectic alloy, we should expect to find, in preparing a eutectic substance, either that actual expansion took place, or that the molecular volume would gradually increase in passing along our curve of melting-points, from either end, for each molecule added, and that it would obtain its greatest value at the point corresponding to the eutectic alloy.
Of this I have no direct evidence as yet, but it is a point of considerable interest, and I may possibly return to it at some future time.—Chemical News.
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Dr. Conrad Berens, of the University of Pennsylvania, reaches the following:
1. Chinoline tartrate is a powerful agent, producing death by asphyxia.
2. The drug increases the force and frequency of the respirations by stimulating the vagus roots in the lung.
3. It paralyzes respiration finally by a secondary depressant action upon the respiratory center.
4. It does not cause convulsions.
5. It lessens and finally abolishes reflex action by a direct action upon the cord, and by a slight action upon the muscles and nerves.
6. It diminishes or abolishes muscular contractility respectively when applied through the circulation or directly.
7. It coagulates myosin and albumen.
8. It causes insalivation by paralysis of the secretory fibers of the chorda tympani; increases the flow of bile; has no action upon the spleen.
9. It lowers blood-pressure by paralyzing the vaso-motor centers and by a direct depressant action upon the heart muscle.