Chapter I: Front Matter

TRANSCRIBER'S NOTES

Italic text is denoted by _underscores_ and bold text by =equal signs=.

The picture of a pointing finger, known in typography as an index, a manicule, or a fist, has been rendered in this text version as "=>".

Subscripts have been rendered using braces, so that the formula for sulphuric acid is shown as "H{2}SO{4}", and the formula for water, if it had appeared, would have been shown as "H{2}O".

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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 at the Paris Exhibition grounds, needs little mention beyond that it is one of those delightful retreats so refreshing to the weary visitor, who, tired out with tramping about the buildings and grounds, is only too pleased to refresh his eyes with some of that exquisite miniature water scenery which is scattered about the grounds. We take our illustration from the London _Graphic_.

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=Improvements in Silk Worm Breeding.=

_Galignani_ states that a very curious discovery has just been made, which, if found as practicable in application as it seems to promise, may create a very considerable change in the production of silk. It is nothing more nor less than the possibility of obtaining two yields in the year of the raw material instead of one, as at present. The moth lays its eggs in May or June, and these do not hatch before the spring of the following year. But sometimes they are observed to hatch spontaneously ten or twelve days after they are laid. It was such a circumstance as this coming to the attention of M. Ducloux, Professor of the Faculty of Sciences at Lyons, that led him to undertake a series of experiments on the subject, by means of which he has found that this premature hatching can be produced at will. The means for effecting the object are very simple--rubbing the eggs with a hair brush, subjecting them to the action of electricity, or more surely still by dipping them for half a minute in concentrated sulphuric acid. M. Bollé, who has also turned his attention to the same subject, states that the same effect is produced by hydrochloric, nitric, or even acetic and tartaric acid. Finally, a submersion of a few seconds in water heated to 50° Cent. (122° Fah.) is equally efficacious. However, M. Ducloux states that the operation must be performed while the eggs are quite young, the second or third day at the outside. When this new hatching is accomplished the mulberry tree is in its full vigor, and the weather so favorable that the rearing of the worm is liable to much less risk than during the early days of spring, when the sudden atmospheric changes are very detrimental, and frequently fatal to the growing caterpillars.

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=The Natural History of the Eel.=

According to the reports of shad fishermen, the chief enemy of the shad is the eel, which not only follows that fish up the streams and devours the spawn, but often attacks the shad after they are caught in the nets. Entering the shad at the gill openings the eels suck out the spawn and entrails, and leave the fish perfectly clean. The finest and fattest shad are the ones selected. It is a curious circumstance that of a fish so well known as the eel so many of its life habits should be in dispute. An animated discussion has been going on in Germany quite recently with regard to the natural history of this fish, and in a late number of a scientific journal the following points are set down as pretty well substantiated. Though a fresh water fish which passes the greater part of its life in rivers, the eel spawns in the sea. That it is viviparous is extremely improbable. The eel found in the upper waters of rivers is almost always female. At the age of four years it goes down to the sea to spawn and never returns to fresh water. The spawning process is somehow dangerous to the eel, thousands being found dead near the mouths of rivers, with their ovaries empty. The descent of the fish to the sea does not appear to take place at any definite period, but is probably dependent on the season for spawning. The male is always much smaller than the female, and never exceeds half a yard in length. The males never ascend to the head waters of rivers, but keep continually in the sea or in the lower reaches of the river. Nothing is definitely known about the spawning season, though it is probable that the eggs are deposited in the sea not far from the mouths of rivers.

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VOL. XXXIX., No. 6. [NEW SERIES.] _Thirty-third Year._
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NEW YORK, SATURDAY, AUGUST 10, 1878.
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=Contents.=

(Illustrated articles are marked with an asterisk.)

American goods, excellence of 89
Astronomical notes* 90
Astronomical observation* 91
Brass, recipe for cleaning [4] 91
Cancer, treatment of 85
Chloride of lime, to neutralize [6] 91
Coal, distillation of* 85
Discoveries, Prof. Marsh's recent 90
Drawings, how to mount [19] 91
Drawings, printing copies of [9] 91
Edison telephone and Hughes' microphone 80
Education, industrial 90
Eel, natural history of the 79
Electro-magnet, to construct [12] 91
England, wages in 85
Engraving, photographic 82
Exhibition, American Institute 84
Export edition, Scientific Amer. 80
Fire, chemicals to extinguish [22] 91
Flour, explosiveness of 87
Gas, saw tempering by natural 87
Germany, labor in 89
Gold, how to melt [18] 91
Hair, removing superfluous [1] 91
Hughes, letter from Prof. 80
Industrial enterprises, new 84
Ink to rule faint lines [7] 91
Inventions, new 86
Inventions, new agricultural 86
Inventions, new engineering 87
Inventions, new mechanical 89
Iron making, progress of 80
Journalism, crooked 88
Lathes, attachment for* 86
Lemon verbena, new use for 89
Life, minute forms of 85
Lime light, how to make [14] 91
Main joints, street 88
Mormons, hint from the 86
N. Y. Capitol, machinery for 87
Paris Ex., Japanese Building* 87
Paris Exhibition, the park* 79
Patent law, our 84
Pens, fountain 80
Petroleum June review 90
Petroleum oils as lubricators 89
Petroleum, short history of 85
Plants, etc., influence of light on 89
Poisoning of a lake, remarkable 90
Production, ill-balanced 89
Production, more perfect 88
Puddling, mechanical* 82
Quick work 86
Rainfall, decrease of N. Y. 86
Rhinoceros Hornbill, the* 87
Shad hatching, successful 88
Shellac, to dissolve bleached [2] 91
Shoes, dressing for ladies' [21] 91
Silk worm breeding 79
Substances, how to rate [3] 91
Sun, the* 80, 81
Teeth, replanting, etc. 84
Telephone, science promoter 80
Thermometer, new deep sea* 83
Timber, ribs on surface of [17] 91
Valve, new steam* 86
Velocipede feat, extraordinary* 89
Wires, copper finish to [24] 91
Wood, to make sound boards [11] 91
Wool product of the world 88
$150,000,000 a year, trying to save 90

TABLE OF CONTENTS OF
=THE SCIENTIFIC AMERICAN SUPPLEMENT=
=No. 136,=
=For the Week ending August 10, 1878.=