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136 Dr. Hartwig's observation, by several other observers, and has now become an object of interest and attention to every one who possesses a telescope. The first observation of it appears to have been by Mr. Isaac W. Ward, of Dunecht, on August 19th. It was not visible at Brussels at the beginning of August; and the Rev. S. H. Saxby, carefully observing the nebula on the 6th, 9th, and 10th of the month at Davos Platz, saw no sign of a stellar nucleus. The telescope at Dunecht on the 5th of September showed it as a star of the 7 magnitude, with a continuous spectrum. At the Greenwich Observatory, on the 4th of September, its spectrum was shown to be of precisely the same character as that of the nebula, or perfectly continuous, with no lines, either bright or dark, visible, and the red end wanting. It therefore presents no evidence of an outburst of heated gas, such as was the case with the "temporary" stars T. Corona in 1866 and "Nova" Cygni in 1876. The appearance of new or temporary stars, though an event that must always excite remark, is not really unusual. One appeared in May, 1859, in the nebula or cluster 80 Mersier, and shone with a magnitude diminishing from the 7th till the 10th of June, when it vanished, and has never been seen since. A similar star was discovered in a nebula in the Unicom in 1861, and is now ranked as a variable star, R. Monoccrotis. The star Eta Argus, in the "key-hole nebula" in Argo, is also a variable star, whose appearance at its brighter stages might suggest to superficial observation the idea of a new or temporary star. It remains to be ascertained whether the present star really belongs to the nebula or is an outsider passing over the line of vision between us and it. Spectroscopic and photometric observations, so far as they have gone, indicate a constitution identical with that of the nebula, but they are not complete. If it does belong to the nebula, a fact mentioned by Mr. R. A. Proctor becomes very important. Mr. Spencer has pointed out that no nebula which could be resolved into stars could possibly lie outside the limits of the galaxy or of the great system of which our solar system is a member; for the outer edges of that system are so far irresolvable. It was generally agreed that, if any nebula lay outside of the system, it was this one in Andromeda. Now, if a star is distinguished in this body, it is clear also that it too must lie within our system.

Shall we raise Silk at a Loss?—In the discussion of a paper by Dr. Riley, in the American Association, advocating tariff "encouragement" of silk-culture in the United States, Mr. Edward Atkinson remarked that the project is not desirable. There is no lack of employment for labor in the United States, as the high rate of wages shows; and the fact that the making of reeled silk has been unprofitable shows that capital can be better employed. Silk-culture is a handicraft simply, and has been carried on by the poorest and most inefficient peoples, who, as they rise in the scale, abandon it, as is now coming to be the case in Southern France. The argument that we shall save the $20,000,000 which we now pay for imported silk is fallacious. When we exchange articles produced by labor costing one dollar per day, for the silk of China or Japan raised by labor costing five or ten cents a day we gain and not lose. We can not afford to do for ourselves what pauper laborers will do for us cheaper.

Chemistry at the American Association.—The Chemical Section of the Association was opened with an address by Professor W. R. Nichols, of the Massachusetts Institute of Technology, on "Chemistry in the Service of Public Health." The author showed that chemistry has an educational office to fill in the service of sanitary science, in teaching the public what its capabilities and limitations are, and correcting the erroneous ideas that are entertained as to the nature of certain processes in preparing food-substances, and the effect in them of the application of particular reagents. Respecting two subjects now much talked of in sanitary circles. Professor Nichols said: "Microbes may well be left to the biologists, and possibly sewer-gas as well, since chemists have failed to discover any substances in the gas which could produce the well-known ill effects. . . . It is asserted by some that the day of chemical examinations is passing away, and that the wholesomeness of water will be determined by the biologist,