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atoms moving about in the solution may be the cause of the clumping or flocculation.  Such electrified atoms are absent from the sugar solution:  sugar does not become “ionised” when it is dissolved.

The suspicion that the free electrified atoms play a part in the phenomenon is strengthened when we recall the remarkable difference in the action of sodium chloride and magnesium chloride.  In each of the solutions of these substances there are free chlorine atoms each of which carries a single charge of negative electricity.  As these atoms are alike in both solutions the different behaviour of the solutions cannot be due to the chlorine.  But the metallic atom is very different in the two cases.  The ionised sodium atom is known to be monad or carries but one positive charge; whereas the magnesium atom is diad and carries two positive charges.  If, then, we assume that the metallic, positively electrified atom is in each case responsible, we have something to go on.  It may be now stated that it has been found by experiment and supported by theory that the clumping power of an ion rises very rapidly with its valency; that is with the number of unit charges associated with it.  Thus diads such as magnesium, calcium, barium, etc., are very much more efficient than monads such as sodium, potassium, etc., and again, triads such as aluminium are, similarly, very much more powerful than diad atoms.  Here, in short, we have arrived at the active cause of the phenomenon.  Its inner mechanism

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is, however, harder to fathom.  A plausible explanation can be offered, but a study of it would take us too far.  Sufficient has been said to show the very subtile nature of the forces at work.

We have here an effect due to the sea salts derived by denudation from the land which has been slowly augmenting during geological time.  It is certain that the ocean was practically fresh water in remote ages.  During those times the silt from the great rivers would have been carried very far from the land.  A Mississippi of those ages would have sent its finer suspensions far abroad on a contemporary Gulf stream:  not improbably right across the Atlantic.  The earlier sediments of argillaceous type were not collected in the geosynclines and the genesis of the mountains was delayed proportionately.  But it was, probably, not for very long that such conditions prevailed.  For the accumulation of calcium salts must have been rapid, and although the great salinity due to sodium salts was of slow growth the salts of the diad element calcium must have soon introduced the cooperation of the ion in the work of building the mountain.

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THE ABUNDANCE OF LIFE [1]

WE had reached the Pass of Tre Croci[2]and from a point a little below the summit, looked eastward over the glorious Val Buona.  The pines which clothed the floor and lower slopes of the valley, extended their multitudes into the furthest distance, among the many recesses of the mountains, and into the confluent Val di Misurina.  In the sunshine the Alpine butterflies flitted from stone to stone.  The ground at our feet and everywhere throughout the forests teamed with the countless millions of the small black ants.