Part 10

Dr. Asa Gray called attention to the interesting discovery of Mr. Meehan regarding the mode of exposing the pollen in the common sunflower. He had found that, contrary to the teachings of the text books, the pistil and stamens develop together until reaching full length, when the filaments rapidly shorten, and the anther tube is retracted, exposing the style covered with pollen, the further changes being the same as usually stated. This Mr. Meehan construed to be a device for self-fertilization; while Dr. Gray showed that, although bees carried pollen from one flower to another of the same head, they also carried it from head to head, which constituted crossing in the fullest sense. An interesting discussion followed, in which Professor Beal suggested that an excellent experiment would be to cover up the heads and ascertain if any fertile seeds were produced. Dr. Gray thought it very likely there would; for, when cross-fertilization is not effected, self-fertilization often takes place. Mrs. Wolcott had proved this to be so; for, in covering up the flowers to keep birds away, she found that plenty of seeds were formed.

Dr. George Vasey, of Washington, gave some notes on the vegetation of the arid plains, which was followed by observations on the curvature of stems of conifers by Dr. Bessey, in which he noted the bending of stems one, two, and even three years old.

Mr. THOMAS MEEHAN discussed the relationship of Helianthus annuns and H. lenticularis; showing that there was a constant difference in the form of the corollas, the former being campanulate, and the latter tubular. The two are treated as one species in Gray's Synoptic Flora of North America; the one being considered a cultivated form of the other, a view from which the speaker dissented. Mr. Meehan then spoke upon the fertilization of composites; concluding that the arrangements were such as to favor self-fertilization, which is opposed to the generally accepted view.

Prof. L. M. Underwood, of Syracuse, N. Y., gave some statistics concerning the North-American Hepaticae. Of the two hundred and thirty-one species found north of Mexico, a hundred and twenty are pecular to America; fully one-half the latter are not represented in any public or private herbarium in this country.

In a paper on the nature of gumming, or gummosis, in fruit-trees, Prof. J. C. Arthur detailed experiments from which the conclusion had been reached that it was due to a deorganization of the cell-walls of the tree through the influence of some fungus, but not necessarily of a specific one.

It had been produced experimentally by the bacteria of pear-blight and by Monilia fructigenum, the fruit-rot fungus; although the most common cause is doubtless the Coryneum, first described by Oudemans in Hedwigia.

At the final meeting the Committee on Postal Matters then gave its report. This committee was appointed at Minneapolis to inquire into the various obstructions which the postal authorities throw in the way of exchanging specimens of dried plants. The efforts of the committee had been directed toward securing the passage of specimens bearing the customary written label at fourth-class rates of postage. The Decision of the Postmaster-General was read, stating that the present law could not be construed to permit the passage of specimens with written labels except at letter-rates, but expressing a willingness to bring the matter, at the proper time, to the attention of Congress, the Canadian authorities, and the congress of the Universal Postal Union. Some discussion followed; and a motion was carried to continue the committee, and also instructing the president and secretary of the club to draft resolutions to be presented to the section of biology, in order to still further promote the objects in view.

These resolutions were acted upon by the biological section on the following day. Dr. Bessey was chosen president, and Professor Arthur secretary, for the next year.

Besides the reading of papers, the club took several excursions. On Saturday they went to the pine-barrens of New Jersey, about fifty participating. On Monday a party visited the ballast-grounds during the morning, and upon their return inspected the library and herbarium of Mr. I. C. Martindale, of Camden, N. J. In the evening of the same day the Botanical section of the Philadelphia Academy of Science entertained the club, the Torrey Botanical Club of New-York City, and other invited guests, at the rooms of the Academy. About three hundred were present, and a thoroughly enjoyable time experienced. On the afternoon of Tuesday the club and its friends, in all about eighty, made an excursion to the Bartram Gardens, one of the most interesting historical spots to botanists in this country; and the club then adjourned.

In reviewing the attendance of botanists in Philadelphia, and the work of the Botanical Club, there is much reason for congratulation. About a hundred entered their names on the register of the club as botanists, or about eight per cent. of the total attendance, one-half of whom are widely known for their attainments in the science. There was no lack of interesting papers and free discussion. Besides the important measures already referred to, the club was instrumental in securing the appointment of a permanent committee of the Association to encourage researches on the health and diseases of plants. But, above all, the augmented facilities for intercourse and acquaintanceship, and the impulse imparted to individual workers, through the influence of the club, are a sufficient _raison d'étre,_ and a promise of usefulness of the future.--_Science_.

PETROLEUM WELLS.

The theory of artesian and of spouting petroleum wells is entirely different. While the latter owe their operation to an internal pressure, due to gases accumulated within a confined space, the former are due to the pressure of a liquid which is flowing--a pressure caused by a sheet of water of unequal height; and they spout with so much the more force in proportion as the difference of level between the orifice and starting point of the sheet of water is greater.

Petroleum reservoirs, or pockets, contain, along with the petroleum, gases, salt water, sand, and foreign substances of varying nature. The liquids and gases in these pockets are often submitted to very great pressure. If we make an aperture in the pocket, there will occur, by reason of the tension, and according to the location of the aperture, a sudden exit of gas, petroleum, salt water, etc. Yet it may happen that as the sounding well has been bored through the upper part of the pocket, where the gases are accumulated, only the latter will make their exit without any trace of petroleum. Under such circumstances the appearance of inflammable gases at the surface indicates pretty certainly the presence of inflammable liquids in the region explored, and will justify further exploration or the fitting of suction pumps to the well holes.

It will be understood that a natural flow of petroleum will occur only so long as the pressure is sufficient, and that a pocket may cease to give mineral oil spontaneously, even though it may still contain large quantities of it. This is the reason why at present spouting wells are not abandoned when they cease to operate, but are worked by lift pumps. The three diagrams, 1, 2, and 3, will give an idea of the different configurations that petroleum pockets may present. In No. 1, as the well hole reaches the summit of the gas chamber, the gases alone will be forced to the surface by reason of the internal pressure, and not the slightest trace of petroleum will accompany them.

In No. 2, as the well ends at the side of the pocket, only a portion of the petroleum--that which is included between the dotted lines--will come to the surface.

In No. 3, as the well ends at the lowest extremity of the pocket, nearly the entire contents of the latter will be forced out naturally. It results from this that in petroleum exploitation the sudden appearance and disappearance of the spouting in no wise proves that the pocket is exhausted.--_Science et Nature_.

ALUMINUM AND ITS ALLOYS.

Symbol, Al. Equivalent, old, 13.7; new. 27.49. Specific gravity, cast, 2.46. Hammered, 2.67. Specific heat, 0.2143, Heat conductivity, 0.66 on silver scale = 100.

Melting point, 1,250° or 1,560° Fah., according to different authorities.

A shining, white, sonorous metal, having a shade between silver and platinum. It is malleable and ductile, does not oxidize when exposed to dry or moist air, and is not chemically affected by hot or cold water.

Sulphureted hydrogen gas, which so readily tarnishes silver, has no action upon this metal.

Having but one defect in its uses as a pure metal (difficulty in soldering), it enters largely as an alloy of other metals, making the baser metals more valuable in resisting oxidation, and as a good as well as cheap imitation of the precious metals.

Its power to ameliorate the condition of the alloys of copper, zinc, tin, iron, nickel, silver, gold, and platinum by portions sometimes less than a thousandth part is beautifully illustrated in the elegant articles of tableware, bric a brac, and ornamental hardware now coming upon the commercial market. Its uses in the mechanic arts in the various forms of bronzes in filling a long wanted requirement of combined ductility, strength, sonorousness, and freedom from oxidation, thus giving to its alloys a high value for articles of house hardware, carriage and harness trimmings, quick running machinery, journal bearings, propeller blades, and artillery. Piano wires made from its alloys will vibrate ten seconds longer than the best now in use.

For the kitchen and for articles for the toilet, there is no more beautiful and cleanly ware. An alloy of silver 20 and aluminum 80 parts by weight, for nautical and other instruments, is without a rival in beauty and lightness; the sea air does not tarnish it.

The aluminum-silver alloys are more valuable than pure silver for table service; its wares will not be destroyed by the constant polishing that wears out our plate, and holds an immunity from the destructive effects of the fatty and acetic acids.

For watch cases it wears cleaner than pure silver, and for watch movements it is far superior to the brass and nickel or German silver heretofore used. An alloy is now made in France that has elastic qualities equal to steel for watch springs, and with the valuable property of being free from magnetic effect.

The aluminum bronzes, when combined with five per cent. of gold, have all the beauty, finish, and durability of color of eighteen carat gold; they are entering largely into the manufacture of watch cases and jewelry.

The composition most approved is made of copper 85, aluminum 10, gold 5, parts by weight. This can be soldered with any of the jeweler's solders of gold, silver, and zinc in the usual way.

The most important alloy, _aluminum bronze_, is composed of aluminum 10 parts, copper 90 parts by weight; specific gravity, 7.7. It has a pale gold color, harder than ordinary bronze, takes a fine polish, is malleable and ductile, but when rolled into sheets requires annealing at every third passage through the rolls, and when drawn into wire must be frequently annealed. It may be forged cold or hot, and can be drawn in tubes. In wire it has a tensile strength of 100,000 lb.

This alloy is often found to be brittle at the first mixing, but becomes ductile after remelting. It is softened while being worked by plunging in water at a low red heat.

The Parisian gold colored alloy is made of aluminum 10.7, copper, 89.3, by weight; used much for cheap French jewelry.

A non-oxidizable alloy in a moist atmosphere: Aluminum, 25, iron 75 = 25 per cent. aluminum. A hard bright alloy, with the properties of silver: Silver 5 (by weight); aluminum 95 = 5 per cent. aluminum.

The silver alloys with aluminum bronze, as represented in the four following atomic formulas, are of a rich gold color, and well adapted for jewelry, watch cases, etc.:

Cu Al Ag Ag + 24 (Al + Cu_{6}) = 0.9180 + 0.0616 + 0.0203 Ag + 24 (Al + Cu_{7}) = 0.9241 + 0.0570 + 0.0188 Ag + 24 (Al + Cu_{8}) = 0.9330 + 0.0504 + 0.0166 Ag + 24 (Al + Cu_{9}) = 0.9400 + 0.0450 + 0.0150

The figures being proportional weights.

A cheap alloy for journal boxes and machinery may be made by substituting zinc for silver in the following atomic proportions:

Cu Al Zn Zn + 2(Al + Cu_{6}) = 0.8643 + 0.0622 + 0.0734 Zn + 2(Al + Cu_{9}) = 0.9053 + 0.0435 + 0.0512 Zn + 2(Al + Cu_{12}) = 0.9273 + 0.0333 + 0.0394

This is subject to considerable shrinkage in casting, but is tenacious, and when drawn into wire has a tensile strength of ninety to one hundred thousand pounds.

The following alloys, in which iron enters as a third element, are well adapted for gun metal, being hard, tenacious, laminable, and ductile:

Cu Al Fe Fe + (Al + Cu_{15}) = 0.9203 + 0.0267 + 0.0530 Fe + (Al + Cu_{9}) = 0.9399 + 0.0446 + 0.0149

Also a four-element alloy of

Cu Al Zn Fe 1. Fe + Zn + (Al + Cu_{12}) = 0.8386 + 0.0305 + 0.0712 + 0.0600 2. Fe + Zn + (Al + Cu_{15}) = 0.8666 + 0.0249 + 0.0588 + 0.0496

The tensile strength of the above alloys as drawn wire is 82,000 pounds for the first, and 107,000 pounds for the second.

All of the alloys in which zinc or zinc and iron enter in place of silver, the color is affected and the luster diminished.

With nickel and platinum for the third element, we have:

Cu Al Ni Ni + 6 (Al + Cu_{6}) = 0.9129 + 0.0634 + 0.0237 Pl + 21 (Al + Cu_{6}) = 0.9117 + 0.0656 + 0.0225

Those alloys into which platinum is introduced are less affected by acids than those in which silver takes the place of platinum; platinum producing a higher luster than silver.

In the alloys of aluminum bronze with the more difficultly fusible metals, it is preferable to fuse the bronze first, then add the other metal in small shavings or wire; by this means the less fusible metal absorbs the other without raising the heat of the furnace excessively. Add the least fusible metal last, a little at a time, allowing the heat of the melted metal to fall by degrees, which prevents boiling and evaporation. The crucibles for mixing the alloys should be of plumbago lined with a paste of lime.

Avoid sand crucibles, as silicium may be reduced and absorbed by the aluminum, inducing brittleness. If found brittle, remelt with cryolite as a flux, or stir the melted metal or alloy with a hard wood stick that has been slightly charred.

In adding aluminum to the copper, cut it in small pieces and push it to the bottom of the crucible with a dry, hard wood stick split so as to hold the pieces.

Sodium chloride (common salt) calcined to evaporate the water, and caustic soda with pulverized charcoal, may be used as a flux for pure aluminum. Avoid borax as a flux, as its metal may suffer reduction, making the aluminum brittle. Aluminum will alloy with tin alone, but is liable to separate on refusion. Does not alloy with lead.

Bismuth, even in minute quantity, makes these alloys brittle.

The East Indian steel called _wootz_ is, according to analysis, alloyed with aluminum. No reliable solder has yet been found for pure aluminum that will flow freely under the blow pipe or from a soldering iron.

A process recently adopted in France is to plate the parts to be united with alloys of tin 5, aluminum 1, upon which tin solder will flow. These proportions may be slightly varied to suit requirements for hardness.

Harder solders to be used with a blowpipe may be made with alloys of zinc, tin, and aluminum.

Aluminum is now made at the works of M. Deville, at Javelle, near Paris, and at Salindres, France; also at Birmingham, England. The product of late has reached the value of $20,000 annually in Europe. It has been claimed to be made in Philadelphia at a reduced cost. The present price in New York is $1.25 per oz. As its bulk is over four times as great as silver, its comparative cost is but one-third that of silver--a point not often considered when the price is quoted.

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TABLE OF CONTENTS.

PAGE

I. CHEMISTRY AND METALLURGY.--Determination of Tannin.--By E. JOHANSON. 7458

The Incomplete Combustion of Gases.--By H. B. Dixon.--Abstract of paper read before the British Association at Montreal. 7458

Aluminum and its Alloys. 7462

II. ENGINEERING AND MECHANICS.--The New Dam at Suresnes.--With engraving. 7453

Bréarey's Aeronautical Machine.--With engraving. 7453

Raising of the Fallen Girder of the Douarnenez Viaduct.--2 engravings. 7454

Improved Wire Testing Machine.--With engraving. 7454

Improved Doubling and Laying Machine.--With engraving. 7454

Boiler Tubes. 7455

Improved Ladle Carriage.--2 figures. 7455

The Repair of Boiler Tubes.--11 figures. 7455

Grulet's Screw for Raising Water.--1 engraving. 7456

III. TECHNOLOGY.--On Various Toning Baths.--Several experiments.--By W. M. ASHMAN. 7456

Coating Plates with Gelatine Emulsion.--5 figures. 7457

Iodo-chloride of Silver Emulsion.--By V. SCHUMANN 7458 Apparatus for Saturating Water with Sulphurous Acid.--1 engraving. 7458

IV. PHYSICS, ELECTRICITY. ETC.--The Wave Theory of Light.--By SIR WM. THOMSON.--Sound and light due to wave vibrations.--Difference between vibrations of light and sound.--Radiant heat.--Solar spectrum.--Luminiferous ether.--How to measure wave lengths of light and the frequency of vibrations.--With diagrams. 7448

The Limitations of Submarine Telegraphy. 7450

Williams' System of Coast Defense by Electrical Torpedoes.--Full page of figures. 7451

New Electric Gas Lighter.--2 figures. 7452

Insulators for Telegraph and Telephone Lines.--9 figures. 7452

Electric Light in Theaters. 7452

Rings of Smoke.--5 figures. 7461

V. ARCHITECTURE.--The New Technical High School at Berlin.--With engraving. 7447

The New University Buildings at Strassburg.--2 engravings. 7447

VI. BOTANY, ETC.--An Improved Hyacinth Glass. 7461

The Botanical Club of the American Association. 7461

VII. HYGIENE, MEDICINE, ETC.--Herbst's Method of Filling.--Demonstrated by Dr. G. C. CLUDINS. 7459

Dr. Koch's Berlin Lecture on Cholera and the Comma Bacillus. 7459

Local Anæsthesia by the Hydrochlorate of Cocaine.--By R. J. LEVIS, M.D. 7459

On Sewage Disposal on Land, by Chemical Treatment, and by Discharge into River or Sea.--By Prof. H. ROBINSON 7460

VIII. MISCELLANEOUS.--New York City Street Cars. 7460

Petroleum Wells. 7462

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[Transcriber's Note:

Inconsistent spelling and hyphenation are as in the original.]