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.

NEW YORK, SATURDAY, AUGUST 10, 1878.

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.

I. ENGINEERING AND MECHANICS.—The Manufacture of Wrought Iron Pipe. Bending the Sheets. Welding the Tube. Manufacture of Gas Pipe. Polishing and Smoothing. 4 figures.

Improved Marine Engine Governor. 1 figure.—Improved Screw Steering Apparatus. 3 figures.—West's Reversing Gear. 1 figure.—Engineering in Peru. The Oroya Railroad over the summit of the Andes. A remarkable engineering feat. The famous Cerro de Pasco Silver Mines. Extensive Coal Fields.

II. TECHNOLOGY.—Coal Ashes as a Civilizer. Grading. Coal Ashes as a Fertilizer.—Utilization of the Waste Waters of Fulling Mills and Woolen Works.—Suggestions in Decorative Art. Marquetry Ornaments from Florence. 3 illustrations.

Useful Recipes. By J. W. Parkinson. Cream cake. Kisses. Apples a la Tongue. Mead. Bread without yeast. Biscuit. Doughnuts. Glaire of Eggs. Crumpets. Ratafia de Framboises. Ratafia de Cerises. To color sugar sand. Raspberry and currant paste. Cheese cake. Cocoanut macaroons. Orange slices. Ice cream. Fruit juices. Lady fingers. White bride cake. Scalloped clams. Iced souffle. Sugar for crystal work. To restore the fragrance of oil of lemon. Family bread.

III. FRENCH INTERNATIONAL EXPOSITION OF 1878.—Tobacco at the Exhibition. Manufacture of snuff. The two processes of fermentation. The grinding. The packing of the snuff. Manufacture of chewing tobacco, etc.

New Cutting Apparatus for Reapers. 1 figure.—The Algerian Court. 1 illustration.—The French Forest Pavilion. 1 illustration.

IV. CHEMISTRY AND METALLURGY.—A Reducing Agent.—Climbing Salts.—Chloride of Lime.—Action of Watery Vapor.—The Active Principles of Ergot.—Cadaveric Alkaloids.

Outlines of Chemistry. By Henry M. McIntire.

V. ARCHITECTURE AND BUILDING.—A Cottage Costing $150. By S. B. Reed, Architect. Plans for cheap summer residence for family of four persons. Dimensions, construction, and estimate for all materials and labor, with 6 figures.—Buildings in Glass. Improved method of constructing conservatories, 2 figures.—Buildings and Earthquakes. On structures in an earthquake country. By John Perry and W. E. Ayrton, Japan. Also a new Seismometer for the measurement of earthquakes.

VI. NATURAL HISTORY, GEOLOGY, ETC.—Colors of Birds and Insects.—Microscopy. Minute and low forms of life. Poisonous Caterpillar. Sphærosia Volvox. An Australian Polyzoon.

A Chinese Tornado.

VII. MEDICINE AND HYGIENE.—Nervous Exhaustion. By George M. Beard, M.D. Symptoms continued. Mental depression with timidity; morbid fear of special kinds; headaches; disturbances of the nerves and organs of special sense; localized peripheral numbness and hyperæsthesia; general and local chills and flashes of heat; local spasms of the muscles. Suggestions and treatment. Electricity. Application of cold; kind of food; exercise; medicines.

The Art of Preserving the Eyesight. V. From the French of Arthur Chevalier. Presbyopy, or long sight. Symptoms. Causes. Artificial light. Franklin's spectacles. Spectacles for artists. Hygiene for long sight, and rules. Myopy, or short sight. Dilation of pupil, and other symptoms of myopy. Glass not to be constantly used in myopy. How to cure slight myopy. Choice of glasses. Colored glasses for short sight. False or distant myopy, and glasses t o be used, 5 figures.

VIII. MISCELLANEOUS.—The Repair of the Burned Models after the Patent Office Fire of 1877. By George Dudley Lawson. An interesting description of the importance and difficulty of the work, and the enterprise and care shown. Reconstructing complicated models from miscellaneous fragments.

Verneuil, Winner of the Ascot Cup, 1 illustration.

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