Chapter 9

Mr. Gime recommends the use of the Latimer-Clark elements. Every one knows that the Latimer-Clark element is now the best standard of electromotive force; but let us not forget that this is on condition of its being employed in open circuit. Now, it is not a question here of an open circuit, nor even of infinitely weak currents, since in the line we have a solenoid whose core must set in motion a whole system of connected pieces. We do not see any possibility of employing Latimer-Clark elements; on the contrary, it seems to us indispensable to select piles of large discharge, since the solenoid, S, will attract nothing at all unless a notable quantity of energy is expended in it.

Is there a pile of this kind so constant as not to render a rigorously accurate adjustment illusory? Therein lies the entire question, and for our part we hesitate to pronounce ourselves in the negative.--_La Lumiere Electrique._

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A CLINICAL LESSON AT "LA SALPETRIERE."

We reproduce the picture of Mr. Andre Brouillet, which was in the Salon of 1887; and that the subject may be better understood, we give the accompanying sketch and description. This picture is very interesting, not only from an artistic point of view, but also as a representation of students and spectators of all ages admirably grouped around a great master of science when most interested in his work. We borrow from _Matin-Salon_ Mr. Goetschy's explanation of the picture:

"The hall in which the lesson is given is lighted by two large windows opening on one of the courts of the hospital. The Professor stands at the right of the picture, his head uncovered, one hand close to his body and the other extended slightly in a gesture which is familiar to him, his audience being before him. At his side is Mr. Babinski, chief of the clinic, supporting a person afflicted with hysteria. Near the latter stands a nurse and assistant who watches every movement of the patient. This is Mother Bottard, a good, intelligent, and devoted woman, who is well known to all those present.

"The auditors have arranged themselves at the students' tables, some seated on the chairs and stools which furnish the room, and others standing, but all following closely the teaching of the master, and at the same time watching the _subject_. The picture is full of life and motion, and yet is very exact. The head and shoulders of the subject are beautifully and correctly drawn. The artist has brought together many men who are well known in literature and science."--_Le Monde Illustre_.

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[NATURE.]

TO FIND THE DAY OF THE WEEK FOR ANY GIVEN DATE.

Having hit upon the following method of mentally computing the day of the week for any given date, I send it you in the hope that it may interest some of your readers. I am not a rapid computer myself, and as I find my average time for doing any such question is about 20 seconds, I have little doubt that a rapid computer would not need 15.

Take the given date in 4 portions, viz., the number of centuries, the number of years over, the month, the day of the month.

Compute the following 4 items, adding each, when found, to the total of the previous items. When an item or total exceeds 7, divide by 7, and keep the remainder only.

_The Century Item_.--For old style (which ended September 2, 1752) subtract from 18. For new style (which began September 14) divide by 4, take overplus from 3, multiply remainder by 2.

_The Year Item_.--Add together the number of dozens, the overplus, and the number of 4's in the overplus.

_The Month Item_.--If it begins or ends with a vowel, subtract the number denoting its place in the year from 10. This, plus its number of days, gives the item for the following month. The item for January is "0;" for February or March (the 3d month), "3;" for December (the 12th month), "12."

_The Day Item_ is the day of the month.

The total thus reached must be corrected by deducting "1" (first adding 7, if the total be "0"), if the date be January or February in a leap year; remembering that every year divisible by 4 is a leap year, excepting only the century years, in new style, when the number of centuries is _not_ so divisible (e.g., 1800).

The final result gives the day of the week, "0" meaning Sunday, "1" Monday, and so on.

EXAMPLES.

1783, _September_ 18.

17 divided by 4 leaves "1" over; 1 from 3 gives "2;" twice 2 is "4."

83 is 6 dozen and 11, giving 17; plus 2 gives 19, i.e. (dividing by 7), "5." Total 9, i.e., "2."

The item for August is "8 from 10," i.e., "2;" so, for September, it is "2 plus 3," i.e., "5." Total 7, i.e., "0," which goes out.

18 gives "4." Answer, "_Thursday_."

1676, _February_ 23.

16 from 18 gives "2."

76 is 6 dozen and 4, giving 10; plus 1 gives 11, i.e., "4." Total "6."

The item for February is "3." Total 9, i.e., "2."

23 gives "2." Total "4."

Correction for leap year gives "3." Answer, "_Wednesday_."

LEWIS CARROLL.

* * * * *

PRECIOUS STONES OF THE UNITED STATES.

To the recently distributed government report on the mineral resources of the United States for 1885.[1] Mr. G.F. Kunz contributes an interesting chapter in which is recorded the progress made during that year in the discovery and utilization of precious stones.

[Footnote 1: Mineral Resources of the United States: Calendar Year 1885. Washington: Government Printing Office. 1888.]

In the summer of 1885, a remarkably large pocket containing fine crystals of muscovite, with brilliant crystals of rutile implanted on them, was found at the Emerald and Hiddenite Mining Company's works, at Stony Point, N.C., and was sold in the form of cabinet specimens for $750. While the soil overlying the rock was being worked, nine crystals of emerald were found, all of which were doubly terminated, and measured from 1 inch to 3-1/8 inches in length and 1-2/3 inch in width. One of these crystals is very perfect as a specimen, being of a fine light green color, and weighing 8¾ ounces. It is held by the company at $1,500, and the nine crystals together at $3,000. Another of these crystals, doubly terminated, measures 2½ inches by 11/12 of an inch, and is filled with large rhombohedral cavities, which formerly contained dolomite. The only crystal from this collection that has been cut into a gem was found in a pocket at a depth of over 43 feet. In color it is of a pleasing light green, and it weighs 4-22/32 carats. No crystal of a finer color has as yet been found in the United States, and the gem is held by the company at $200.

During the recent mining, the largest fine crystal of lithia emerald ever found was also brought to light. It measures 2¾ inches by 3/5 of an inch by 1/3 of an inch. One end is of a very fine color, and would afford the largest gem of this mineral yet found, and one which would probably weigh 5½ carats. With this there was a number of superior crystals and some ounces of common pieces of the same mineral. The company estimates the value of this entire yield of hiddenite at about $2,500.

There was also found a quantity of quartz filled with white byssolite, forming very attractive specimens and valued at $250.

A number of beryls of a fine blue color, resembling the Mourne Mountain specimens, were found near Mount Antero, Chaffee County, Col. One of these was 4 inches long and 3/8 of an inch across, with cutting material in it. The other crystals measured from 1 to 1¼ inch in length, and from 1/5 to 1/3 inch in width.

The large beryl mentioned by Mr. Kunz in the Mineral Resources for 1883 and 1884 has afforded the finest aquamarine of American origin known. It is brilliant as a cut gem, and, with the exception of a few internal hair-like striæ, is absolutely perfect. It weighs 133¾ carats, measures 1-2/5 × 1-2/5 × 4/5 inch, and is of a deep bluish green, equal to that of gems from any known locality.

Mr. G.F. Breed, manager of the Valencia Mica Company, has cut nearly one hundred aquamarines, ranging from ½ carat to 4 carats in weight, and of a light blue color, from white beryls found in the company's mica mine at North Grafton, N.H.

A number of fine, deep golden-yellow, blue, and green beryls, equaling any ever found, have been taken by Mr. M.W. Barse from his mica mine between New Milford and Litchfield, Conn. Some fine blood-red garnets from this same locality have been cut into gems.

The largest phenacite crystal ever found is owned by Mr. Whitman Cross. It was discovered at Crystal Park, Col., weighs 59 pennyweights 6 grains, and measures 1-4/5 inch in length and 1-1/5 inch in thickness.

Thousands of garnet crystals, found at Ruby Mountain, near Salides, Col., have been made into paperweights and sold to tourists. Those that weigh a few ounces sell for about ten cents each. One was sold that weighed 14 pounds. Apropos of garnets, the discovery, in the heart of New York city, of as fine a crystal as was ever found on this continent, and weighing 9 pounds 10 ounces, may be mentioned as a matter of peculiar interest.

Several thousand dollars' worth of the wood jasper of Arizona has been cut into paper weights, charms, and other objects, or polished on one side for cabinet specimens. Numbers of these articles are now being cut and sold to tourists along the line of the Atchison, Topeka, and Santa Fe Railroad.

The compact quartzite of Sioux Falls, Dakota, is being quarried and polished for ornamental purposes. It is known and sold as "Sioux Falls jasper," and is really the stone referred to by Longfellow in his Hiawatha as being used for arrow heads. This stone takes a very high polish, and is found in a variety of pleasing tints, such as chocolate, brownish-red, brick-red, and yellowish. For the two years previous to 1885, $15,000 worth of it was sold.

A remarkable mass of rock crystal has been received by Messrs. Tiffany & Co. from a locality near Cave City, Va. Although this mass weighs 51 pounds, it is but a fragment of the original crystal, which weighed 300 pounds, and which was broken in pieces by the ignorant mountain girl who found it. The fragment, as it is, will furnish slabs 8 inches square and from 1/3 to 1 inch thick. The original crystal would have furnished a ball from 4½ to 5 inches in diameter, and almost perfect. A number of fine agates of various kinds were found by Mr. F.C. Yeomans at the same locality.

The meccanite from Cumberland, R.I., is often spotted with white quartz. It has been cut into oval stones several inches in length, which take a fine polish. This quality, coupled with its hardness, makes it a desirable ornamental gem stone.

Mr. Kunz records the discovery, by himself, in the largest mass of the Glorieta Mountain (Santa Fe County, N.M.), of pieces of peridot of sufficient transparency to afford gems one-fifth of an inch in length.

Large quantities of turquoise from Los Cevillos, N.M., have been sold, both as cabinet specimens and gems; but, unfortunately, many of those of the finest color have been found to be artificially colored.

Malachite in large masses has been found at the Copper Queen mine at Bisbee, Oregon. One of these masses weighed 15 pounds and others were quite as large. All were of good enough quality and large enough for table tops.

In conclusion, Mr. Kunz says that "the National Museum collection of gems, formed by Prof. F.W. Clarke, is now one of the most complete, for species, in the United States, and as many of the gems are of more than average merit, and all can have access to them, this is one of the best opportunities afforded the student in this country."

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THE BRAZIL NUT.

Every one is acquainted with the hard-shelled, triangular fruit called the Brazil nut, but there are, perhaps, but few who know anything about the tree that produces it, or its mode of growth. The Brazil nut tree belongs to a genus of Lecythidaceæ of which there is only one species, _Bertholletia excelsa_. This tree is a native of Guiana, Venezuela, and Brazil. It forms large forests on the banks of the Amazons and Rio Negro, and likewise about Esmeraldas, on the Orinoco, where the natives call it _juvia_. The natives of Brazil call the fruit _capucaya_, while to the Portuguese it is known as _castaña de marañon_.

The tree is one of the most majestic in the South American forests, attaining a height of 100 or 150 feet. Its trunk is straight and cylindrical, and measures about 3 or 4 feet in diameter. The bark is grayish and very even. At a distance, the tree somewhat resembles a chestnut. Its branches are alternate, open, very long, and droop toward the earth. The leaves are alternate, oblong, short petioled, nearly coriaceous, about 2 feet long by 6 inches wide, entire or undivided, and of a bright green color. The flowers have a two-parted, deciduous calyx, six unequal cream-colored petals, and numerous stamens united into a broad, hood-shaped mass, those at the base being fertile, and the upper ones sterile.

The fruit is nearly orbicular, and about 6 inches in diameter, and has a hard shell about half an inch thick, which contains from 18 to 24 triangular, wrinkled seeds that are so beautifully packed within the shell that when once disturbed it is impossible to replace them. When these fruits are ripe, they fall from the tree and are collected into heaps by troops of Indians called _Castanhieros_, who visit the forests at the proper season of the year expressly for this purpose. They are then split open with an ax, and the seeds (the Brazil nuts of commerce) taken out and packed in baskets for transportation to Para in the native canoes. The "meat" that the Brazil nut contains consists of a white substance of the same nature as that of the common almond, and which is good to eat when fresh, but which, by reason of its very oily nature, soon gets rancid. Besides its use as an article of dessert, a bland oil, used by watchmakers and artists, is obtained from the nut by pressure. Brazil nuts form a considerable article of export from the port of Para, whence they are sometimes called Para nuts.

The Brazil nut tree remained for a long time unknown to European botanists, although the fruit has been from a very remote epoch consumed in large quantities in certain southern countries of the New World. The first description of the tree we owe to Humboldt and Bonpland, who established the genus and species in the botanical part of the account of their voyage. The genus is dedicated to the illustrious Berthollet.

"We were very fortunate," say these authors, "to find some of these nuts in our travels on the Orinoco. For three months we had been living on nothing but poor chocolate and rice cooked in water, always without butter, and often without salt, when we procured a large quantity of the fresh fruits of the _Bertholletia_. It was along in June, and the natives had just gathered them."

The formation of a large woody fruit, often in the shape of an urn, from which the top spontaneously separates in the form of a lid, is one of the characteristics of the order Lecythidaceæ, which includes the _Couronpita Guianensis_, or "cannon ball tree"; the gigantic _Lecythis ollaria_, or "monkey-pot tree," whose great woody pericarps serve as drinking vessels; and the _Lecythis Zabucajo_, whose fruit is known in the market as sapucaia nuts, and is greatly superior to the closely allied Brazil nuts as regards flavor and ease of digestion.

All the trees of this order are natives of South America, and especially of Guiana.

* * * * *

THE ACTION OF THE MAGNET IN HYPNOSIS.

Mr. Tamburini some time ago observed that, during a period of lethargy, the approach of a magnet produced in persons affected with hysterical hypnosis a series of modifications of the respiratory functions and of contractility.

From some very careful experiments made by him and Mr. Righi in common, upon the lady who was the principal subject of his observations, it results that (1) it makes no difference whether the magnet be presented by its poles or its neutral line; (2) that any mass of metal whatever acts like a magnet; (3) that an electromagnet produces exactly the same effect whether it be or be not excited by a current; and (4) that a glass tube filled with cold or warm water likewise produces analogous effects, which disappear when the water is raised to the temperature of the human body.

It seems, therefore, that the magnetic properties of the magnet count for nothing in the phenomena observed.--_Journal de Physique_.

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