in such rocks, and then has the following as to how they came there: "There is every probability that originally the enveloping matrix must have reached the fossils in the shape of volcanic ash, or, more likely still, in the shape of a thick fluid sediment enveloping the trunks of the trees as they stood erect, with their broken branches, leaves, and fruit scattered around them. We have numerous instances of ash-beds overlying limestone-beds containing corals, and I suspect Mr. Honeyman's 'trap rock in a fluid state' would resolve itself into a rock of the nature above indicated; at all events, it would be very interesting to geologists on this side to receive specimens for closer examination. With regard to the possibility of fossils being inclosed and preserved in fluid lava, I may mention that when at Catania, in 1867, I was informed by Prof Sylvestri that oak-trees on Mount Etna, when overtaken by lava-streams, are not actually annihilated, but the lava forms a sort of hollow cylinder around the trees, in which they are carbonized, and the silex contained in the wood collects in a fused mass at the bottom of the trunk. Such fused masses I met with at the foot of some of the stems of trees excavated by me at Arran, and numerous pebbles, evidently derived from the same source, are to be picked up on the shore between the Fallen Rocks and the Scriden at the north end of Arran."
Curious Method of capturing Musk-rats.—The American Sportsman describes the ingenious method followed by trappers in catching musk-rats: These animals often travel great distances under ice. In their winter excursions to their feeding-grounds they take in breath at starting, and remain under water as long as they can. They then rise to the ice and exhale the air in their lungs; this remains in bubbles against the under surface of the ice. They wait till this air recovers oxygen from the water and ice, and then, reinhaling it, go on till the operation has to be repeated. In this way they can travel almost any distance, and live any length of time, under the ice. The trapper takes advantage of this habit. When the marshes and ponds where musk-rats abound are frozen over, and the ice is comparatively thin and clear, they can be seen swimming about beneath. Following one for some distance, the trapper sees it come up to renew its breath in the manner described. After the animal has exhaled, and before it has time to take in the reoxygenized air in the bubbles again, he strikes with his hatchet directly over it, scattering the bubbles, and driving the musk-rat away. In this case the rat drowns in swimming a few rods, and the trapper, cutting a hole in the ice, takes it out. Mink, otter, and beaver, travel under the ice in the same way, and hunters, it is, stated, frequently take otters in the same manner.
Education of Telegraph-Operators.—In Holland the applicant for apprenticeship in a telegraph-office is required to present a thesis in Dutch; to be acquainted with French, English, and German; to know the first principles of arithmetic, common and decimal fractions, and the metrical system of weights and measures; to have mastered the rudiments of algebra and geometry, and in geography to be familiar with the situation of the various countries and principal towns. When an apprentice applies for the position of a telegraphist of the third class, he is required to pass an examination in magnetism, electro-magnetism, etc.—in short, to prove his familiarity with every detail of telegraph administration. Remarking on this, the Journal of the Telegraph says that in this country the person who enters the telegraphic service "must certainly know his telegraphic letters and make them correctly; must write a clear hand; must have a knowledge of circuits and office connections; and must be informed respecting the company's rules. Yet these simple requirements are objected to. 'I fear,' says the manager of a large office, 'if this were required here, I should be left almost alone.' We ask, 'Can this ignorance of the commonest knowledge of a great business be true?' We fear it is."
How Water is injured by Organic Matter.—In a recent work entitled "Scientific Conversations," by M. Porville, of Paris, the reason why organic matter becomes a dangerous constituent of water is thus set forth: "How does organic matter become dangerous? We must not behave that it
