water in the aquaria can be kept at any desired temperature throughout the year. This will give an opportunity, not only for keeping alive a number of different kinds of animals that will not live at ordinary temperatures, but will also give to the investigator a chance to carry out important researches on the effect of different temperatures on marine forms.
The addition to the station will double its working capacity, since the new part will be entirely devoted to investigation, while in the two older buildings there are the public aquaria, the collecting department, and the library. Zoology, botany physiology, physiological-chemistry and psychology will benefit the world over by this enlargement of the Naples Station. Professor Dohrn deserves to be heartily congratulated that his labors have been crowned by success. May the time come before long when the station will be made symmetrical by the addition of a fourth building!
ARE SOLUTIONS MECHANICAL MIXTURES OR NEW SUBSTANCES?
In a recent volume Duhem sketches the development of our ideas in regard to solutions. If we drop a lump of sugar into a glass of water, the sugar disappears and we have in the tumbler a colorless liquid which looks like water, but which has a different taste. We are all agreed as to the fact, but there has always been a difference of opinion as to what became of the sugar. One view is that the sugar and water are still there, but so finely divided that we do not see the sugar. If we grind a little dry sugar together with a good deal of charcoal, we get a black mixture in which the eye does not detect the sugar though the sugar is unqestionably there. Another view is that we have neither water nor sugar in the tumbler, but a new substance having properties differing more or less completely from those of the sugar and water. This is the view that we take in regard to sugar itself when we speak of it as made up of charcoal and water. The first view, of a mechanical mixture, was held by the Greek atomistic philosophers under Epicurus while the second view was defended by Aristotle and the peripatetic philosophers. Through the Middle Ages, the views of Aristotle prevailed; but Bacon and Descartes brought the atomistic view to the front
