A WEEKLY JOURNAL OF PRACTICAL INFORMATION, ART, SCIENCE, MECHANICS,CHEMISTRY, AND MANUFACTURES.

Vol. XXXIX.—No. 6	NEW YORK, AUGUST 10, 1878	$3.20 per Annum.
[NEW SERIES.]		[POSTAGE PREPAID.]

THE PARIS EXHIBITION.—A SKETCH IN THE PARK.

Our engraving, which represents a portion of the park atthe Paris Exhibition grounds, needs little mention beyondthat it is one of those delightful retreats so refreshing to theweary visitor, who, tired out with tramping about the buildingsand grounds, is only too pleased to refresh his eyes withsome of that exquisite miniature water scenery which is scatteredabout the grounds. We take our illustration from theLondon Graphic.

Improvements in Silk Worm Breeding.

Galignani states that a very curious discovery has justbeen made, which, if found as practicable in application asit seems to promise, may create a very considerable changein the production of silk. It is nothing more nor less thanthe possibility of obtaining two yields in the year of the rawmaterial instead of one, as at present. The moth lays itseggs in May or June, and these do not hatch before thespring of the following year. But sometimes they are observedto hatch spontaneously ten or twelve days after theyare laid. It was such a circumstance as this coming to theattention of M. Ducloux, Professor of the Faculty of Sciencesat Lyons, that led him to undertake a series of experimentson the subject, by means of which he has found that thispremature hatching can be produced at will. The meansfor effecting the object are very simple—rubbing the eggswith a hair brush, subjecting them to the action of electricity,or more surely still by dipping them for half a minutein concentrated sulphuric acid. M. Bollé, who has alsoturned his attention to the same subject, states that thesame effect is produced by hydrochloric, nitric, or evenacetic and tartaric acid. Finally, a submersion of a fewseconds in water heated to 50° Cent. (122° Fah.) is equallyefficacious. However, M. Ducloux states that the operationmust be performed while the eggs are quite young, the secondor third day at the outside. When this new hatching isaccomplished the mulberry tree is in its full vigor, and theweather so favorable that the rearing of the worm is liableto much less risk than during the early days of spring, whenthe sudden atmospheric changes are very detrimental, andfrequent

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