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plunging the end of the longer tube in a vessel of water. The instrument may now be fixed in this position, as an intermittent jet of water begins to flow at once, continuing until the flask is empty. The column of water in the longer tube will be seen to be alternately rising and falling, from which phenomena an explanation has been given of the cause of the intermittent flow.—Popular Science Review.

The Dorse, or Variable, or Baltic Cod-fish (Morrhua callarias).—This Cod is rare in the British islands, Yarrell never having seen it, but in the north of Europe it is abundant, and I get it from the Baltic Sea at Kiel, and less abundantly from Heligoland. Consequently, the Hamburg aquarium always contains living specimens, and it thrives well in captivity, as indeed most fishes will thrive, if kept in large tanks furnished with a constantly running stream of water, and a proper supply of food. The Dorse under my care consume great quantities of oysters, mussels, earthworms, dead fresh-water fish, prawns, shrimps, and indeed all animal matters except sea anemones, which no fish that I know of will touch, if ever so hungry. Indeed, these Cods have with me grown so rapidly as to become a nuisance, from their habit of devouring all other fish—even their own species—lesser than themselves, in the same tank, and I had to return some of them to the sea and get smaller ones in their place. But one of the original stock I retained, and it grew from five to thirteen inches long in a year. It became quite tame—or rather fearless—and it would at feeding time regularly lie on the top of one particular flat stone, and take its oyster or mussel out of my fingers. I am afraid to add that it would then allow me to stroke its head, as I may be disbelieved by those persons who did not see it; but so it certainly was; I stroked its head with my hand every day, as regularly as I stroke that of my cat. This fish at length went the way of most pets; it sprang over the side of its tank one night, and next morning it was found on the floor, dead and stiff. I send some to the aquarium of the Zoological Society of London, and I hear that they soon died.—W. Alford Lloyd, Zoological Gardens, Hamburg.

The "Germon" (Orcynus alalonga).—Dr. Scott has recorded the occurrence of this rare fish on the coast of Devonshire. Three specimens had before this been taken on the English coast, and the fish is figured in "Couch's British Fishes" (vol. ii., pl. 84, p. 100). It is the Long-finned Tunny of some authors, and is abundant on the south coasts of Europe, where it is the object of extensive fisheries. The specimen captured was twenty-four inches in length and weighed twelve pounds. It somewhat resembles a gigantic mackerel.

Muller's Topknot.—In the second week of September last, while fishing with a net off Caldy Island, Pembrokeshire, we caught a specimen of Muller's Topknot, about ten inches in length, a fish very rare in those parts, and unknown to any of the fishermen.—E. K. B.

The Sturgeon.—On Thursday, the 5th inst., a fine specimen of that rare fish in English waters, the Sturgeon, was left stranded by the receding tide near Aveton Gifford Bridge, on the Devonshire Avon, three or four miles from the coast of Bigbury Bay. The fish was six feet ten inches in length. It was captured by a labourer, who, as I am informed, sold it to a neighbouring miller for five shillings, the purchaser forthwith sending it by train to London and realising £15 by its sale there. It may be worth remarking that the Sturgeon is one of the very few existing species of the Ganoid order, to which so large a number of our fossil fishes are referable.—Horace Waddington.

Fish Scales for the Microscope.—The eel affords a beautiful object for this purpose. The scales are covered by a thin "skin," which may be slightly raised with a knife and then torn off. The required portion may then be removed; or if a piece of skin can be procured as stripped off in cooking, the scales may be easily taken from the inner surface. They must then be washed and thoroughly cleaned. After drying, soak for a day in turpentine, and mount in the ordinary manner with balsam. This is a good polarizing object; but the interest, and I think the beauty, is increased by procuring a piece of eel's skin with the scales in situ, washing and drying under pressure, and mounting in balsam as before. The arrangement of the scales produces beautiful "waves" of colour, which are quite soothing to the eye after examining some of the very gorgeous salts, &c.—Davies on Mounting.

Light in the Ocean.—I am often reminded of the small amount of light existing in the sea, by noticing that when I first receive crabs, lobsters, and some other similar animals, their shells are quite clean, but after I have had them for some time in the aquarium under my care here, they become gradually covered with conferva and other parasitic plants, the growth of which depends upon the amount of light they obtain; and yet the tanks are darkened to an extent which does not do more than permit the animals to be seen. There is never any glare of light; the front halves of the tops of the tanks are boarded over, sot that the light enters only by the hinder halves, and even then some blinds are carefully drawn over them. In addition, these crustacea are permitted to hide in holes in the rock-work of the tanks. It is only when they are taken out of the tanks and placed in reservoirs completely darkened, that the parasitic plants die away.—W. Alford Lloyd.