Chapter 8

Dec., 1874. Dec., 1884. Per lb. Per lb. £ s d. £ s. d. Osmium 71 10 0 62 0 0 Iridium 70 0 0 45 0 0 Gold 62 15 0 63 0 0 Platinum 25 7 6 21 7 6 Thallium 23 17 6 4 15 0 Magnesium 10 5 0 1 15 0 Potassium 5 0 0 4 0 0 Silver 3 17 6 (in Hamburg) 3 7 6 Aluminum 1 16 0 1 16 0 Cobalt 1 14 0 1 2 0 Sodium 0 14 2 0 8 8 Nickel 0 11 0 0 3 1 Bismuth 0 8 1 0 8 1 Cadmium 0 7 1 0 4 0 Quicksilver 0 2 0 (in London) 0 1 9 Tin 0 1 1 (in Berlin) 0 0 9 Copper 0 0 10 (" " ) 0 0 7 Arsenic 0 0 8 0 0 4-1/2 Antimony 0 0 6-1/4 (" " ) 0 0 5 Lead 0 0 2-3/4 (" " ) 0 0 1-3/8 Zinc 0 0 2-1/2 (" " ) 0 0 1-3/4 Steel 0 0 1-3/8 ( in 0 0 0-3/4 Bar iron 0 0 1-1/8 Upper 0 0 0-5/8 Pig iron 0 0 0-7/16 Silesia ) 0 0 0-1/4

Gold now ranks highest in value of all metals, the competition of osmium and iridium having been over come. It is only by reason of improved methods of preparation that the latter have become cheaper, while their use has at the same time increased. Iridium is mixed with platinum in order to increase its strength and durability. The normal standards of the metrical system are made of platinum-iridium on account of its known immutabilty. In 1882, platinum stood 15 per cent. below its present value; but its increased employment for industrial purposes led to the subsequent improvement in price. Thallium has experienced a severe depreciation on account of the economical process by which it is extracted from the residue of the lead chambers used in the manufacture of sulphuric acid. The use of this metal is mainly confined to experimental purposes. The fall in silver has arisen from increased production and diminished use for coinage.

Magnesium was scarcely of any industrial value prior to the fall in price now recorded. Improved processes for its treatment have successfully engaged the attention of scientific men, and it is now capable of being used as an alloy with other metals. The Salindres factory regulates the price to a certain extent, and its system of working is regarded as a guide in the various processes connected with this branch of industry. The manufacture of potassium and sodium will, it is expected, be more fully elucidated than hitherto, by means of researches made at Schering's Charlottenburg factory. The course of nickel prices illustrates the stimulus to economical production afforded by an increased consumption. This latter fact is principally due to the employment of nickel for coinage, as alloy for alfenide, etc. The use of cadmium is materially restricted by its relatively limited supply. Hitherto, its only source was in the incidental products of zinc distillation, but of late it has been attempted to bring it into solution from its oxide combinations. An increased employment of cadmium for industrial purposes is expected to follow.

Production in excess of the demand has caused the depreciation recorded in tin, and various other metals not commented upon, this remark applying even to the scarce metals, arsenic and antimony. Even the better marks of Cornwall tin and Mansfield refined copper have had to follow the downward course of the market.

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A PERPETUAL CALENDAR.

The annexed figure represents a perpetual calendar, which any one can construct for himself, and which permits of finding the day that corresponds to a given date, and conversely.

The apparatus consists of a certain number of circles and arcs of circles divided by radii. The ring formed by the two last internal circles is divided into 28 equal parts, which bear the names of the week, the first seven letters of the alphabet in reversed order, and two signs X. The circle formed by the external circumference of the ring constitutes the movable part of the apparatus, and revolves around its center. Two circular sectors, which are diametrically opposite, are each divided into seven parts and constitute the fixed portions. In the divisions of the upper sector are distributed the months, according to the order of the monthly numbers. In the other sector the days of the month are regularly distributed. In order to render the affair complete, a table is arranged upon the movable disk for giving the annual numbers, or rather, in this case, the annual letters. The calendar is used as follows: Say, for example, we wish to find what days correspond to the different dates of August, 1885; we look in the table for the letter (D) that corresponds to this year; then we bring this letter under the given month (August) and the days marked upon the movable disk corresponding to the dates sought, and it only remains to make a simple reading.

It will be seen that the leap-years correspond to two letters. We here employ the first to Feb. 29 inclusive, and the second for the balance of the year. The calendar may be made of cardboard, and be fixed to wood.--_La Nature._

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AN ACCOMPLISHED PARROT.

Around the door of a Sixth Ave. bird store near Twenty-third St. was gathered the other day a crowd so large that it was a work of several minutes to gain entrance to the interior. From within there proceeded a hoarse voice dashed with a suspicion of whisky, which bellowed in Irish-American brogue the enlivening strains of "Peek-a-boo." With each reiteration of "Peek-a-boo" the crowd hallooed with delight, and one small boy, in the exuberance of his joy, tied himself into a sort of knot and rolled on the pavement. Suddenly the inebriated Irishman came to a dead stop, and another voice, pleasanter in quality, sang the inspiring national ode of "Yankee Doodle," followed by the stentorian query and answer all in one, "How are the Psi-Upsilon boys? Oh, they're all right!"

A passer-by, puzzled at the scene, made his way into the store and soon solved the mystery. In a large cage in the center was an enormous green and yellow parrot, which was hanging by one foot to a swinging perch, and trolling forth in different voices with the ease of an accomplished ventriloquist. He resumed a normal position as he was approached, and flapping his wings bellowed out, "Hurrah for Elaine and Logan!" Then, cocking his head on one side, he dropped into a more conversational tone, and with a regular "Alice in Wonderland" air remarked: "It's never too late to mend a bird in the hand;" and again, after a pause, "It's a long lane that never won fair lady." His visitor affably remarked:

"You're quite an accomplished bird, Polly," and quick as a flash the creature replied:

"I can spell, I can. C-a-t, cat. D-o-g, fox," with an affectation of juvenility which was grewsome. He resented an ill-advised attempt at familiarity by snapping at the finger which tried to scratch his poll, and barked out:

"Take care! I'm a bad bird, I am. You betcher life!"

"He's one of the cleverest parrots I have had for some time," said his owner, Mr. Holden. "In fact, he is almost as good as Ben Butler, whom I sold to Patti. His stock of proverbs seems inexhaustible, and he makes them quite funny by the ingenious way in which he mixes them up. I could not begin to tell you all the things he says, but his greatest accomplishment is his singing. He is a double yellowhead--the only species of parrot which does sing. The African grays are better talkers, but they do not sing. They only whistle. What do I ask for him? Oh, I think $200 is cheap for such a paragon, don't you?"--_N.Y. Tribune._

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THE ROSCOFF ZOOLOGICAL LABORATORY.

The celebrated Roscoff zoological station was founded in 1872, and has therefore been in existence for thirteen years; but it may be said that it has changed appearance thirteen times. Those who, for the last six or seven years, have gone thither to work with diligence find at every recurring season some improvement or new progress.

A rented house, a small shed in a yard, little or no apparatus, and four work rooms--such was the debut of the station; and modest it was, as may be seen. Later on, the introduction of a temporary aquarium, which, without being ornamental, was not lacking in convenience, sufficed for making some fine discoveries regarding numerous animals.

A small boat served for supplying necessaries to the few workers who were then visiting Roscoff; but as the number of these kept gradually increasing, it became necessary to think of enlarging the station, and the purchase of a piece of property was decided upon. Since then, Mr. Lacaze Duthiers has done nothing but develop and transform this first acquisition. A large house, which was fitted up in 1879, formed the new laboratory. This was built in a large garden situated nearly at the edge of the sea. We say _nearly_, as the garden in fact was separated from the sea by a small road. The plan in Fig. 1 shows that this road makes an angle; but formerly it was straight, and passed over the terrace which now borders upon the fish pond. How many measures, voyages, and endless discussions, and how much paper and ink, it has taken to get this road ceded to the laboratory! Finally, after months of contest, victory rewarded Mr. Duthiers's tenacity, and he was then able to begin the construction of a pond and aquarium. All this was not done at once.

Another capital improvement was made in 1882. The public school adjoining the establishment was ceded to it, the separating walls fell, the school became a laboratory, the class rooms were replaced by halls for research, and now no trace of the former separation can be seen--so uniform a whole does the laboratory form. No one knows what patience it required to form, piecemeal as it were, so vast an establishment, and one whose every part so completely harmonizes.

During the same year a park, one acre in area, was laid out on the beach opposite the laboratory. This is daily covered by the sea, and forms a preserve in which animals multiply, and which, during the inclement season, when distant excursions are impossible, permits of satisfying the demands that come from every quarter. All, however, is not finished. Last year a small piece of land was purchased for the installation of hydraulic apparatus for filling the aquarium. This acquisition was likewise indispensable, in order to prevent buildings from being erected upon the land and shutting off the light from the work rooms opposite. Alas, here we find our enemy again--the little road! Negotiations have been going on for eighteen months with the common council, and, what is worse, with the army engineers, concerning the cession of this wretched footpath.

The reader now knows the principal phases of the increases and improvements through which the Roscoff station has passed. If, with the plan before his eyes, he will follow us, we will together visit the various parts of the laboratory. The principal entrance is situated upon the city square, one of the sides of which is formed by the buildings of the station. We first enter a large and beautiful garden ornamented with large trees and magnificent flowers which the mild and damp climate of Roscoff makes bloom in profusion. We next enter a work room which is designed for those pupils who, doing no special work, come to Roscoff in order to study from nature what has been taught them theoretically in the lecture courses of schools, etc. There is room here for nine pupils, to each of whom the laboratory offers two tables, with tanks, bowls, reagents, microscopes, and instruments of all kinds for cabinet study, as well as for researches upon animals on the beach. Here the pupils are in presence of each other, and so the explanations given by the laboratory assistants are taken advantage of by all. At the end of this room, on turning to the left, we find two large apartments--the library and museum. Here have been gradually collected together the principal works concerning the fauna of Roscoff and the English Channel, maps and plans useful for consultation, numerous memoirs, and a small literary library. The scientific collection contains the greater portion of the animals that inhabit the vicinity of Roscoff. To every specimen is affixed a label giving a host of data concerning the habits, method of capture, and the various biological conditions special to it. In a few years, when the data thus accumulated every season by naturalists have been brought together, we shall have a most valuable collection of facts concerning the fauna of the coast of France. Two store rooms at the end of these apartments occupy the center of the laboratory, and are thus more easy of access from the work rooms, and the objects that each one desires can be quickly got for him.

After the store rooms comes what was formerly the class room for boys, and which has space for three workers, and then the former girls' class room, which has space for eight more. Let us stop for a moment in this large room, which is divided up into eight stalls, each of which is put at the disposal of some naturalist who is making original researches. Fig. 2 represents one of these, and all the rest are like it. Three tables are provided, the space between which is occupied by the worker. Of these, one is reserved for the tanks that contain the animals, another, placed opposite a window giving a good light, supports the optical apparatus, and the last is occupied by delicate objects, drawings, notes, etc., and is, after a manner, the worker's desk. Some shelving, some pegs, and a small cupboard complete the stall. It is unnecessary to say that the laboratory furnishes gratuitously to those who are making researches everything that can be of service to them.

Four of these stalls are situated to the north, with a view of the sea, and the other four overlook the garden. They are separated from each other by a simple partition, and all open on a wide central corridor that leads to the aquarium. Before reaching the latter we find two offices that face each other, one of them for the lecturer and the other for the preparator. These rooms, as far as their arrangement is concerned, are identical with the stalls of the workers. The laboratory, then, is capable of receiving twenty-three workers at a time, and of offering them every facility for researches.

The aquarium is an immense room, 98 ft. in length by 33 in width, glazed at the two sides. It is at present occupied only by temporary tanks that are to be replaced before long by twenty large ones of 130 gallons capacity, and two oval basins of from 650 to 875 gallons capacity, constructed after the model of the one that is giving so good results at Banyuls. At the extremity of the aquarium there is a store room containing trawls, nets of all kinds, and mops, for the capture of animals. Here too is kept the rigging of the two laboratory boats, the Dentale and Laura. Above the store room is located the director's work room.

A wide terrace separates the aquarium from the pond. This latter is 38 yards long by 35 wide. Thanks to a system of sluice valves, it is filled during high tide, and the water is shut in at low tide, thus permitting of having a supply of living animals in boxes and baskets until the resources of the laboratory permit of a more improved arrangement. This basin is shown in Fig. 3. It is at the north side of the laboratory as seen from the beach. Here too we see the aquarium, the garden, and a portion of the shore that serves as a post for the station boats.

We must not, in passing, fail to mention the extreme convenience that the proximity of the aquarium work room to the pond and sea offers to the student.

This entire collection of halls, constituting the scientific portion of the laboratory, occupies the ground floor. The first and second stories are occupied by sleeping apartments, fourteen in number. These, without being luxurious, are sufficiently comfortable, and offer the great advantage that they are very near the work rooms, thus permitting of observing, at leisure, and at any hour of the day or night, the animals under study.

Everything is absolutely free at the laboratory. The work rooms, instruments, reagents, boats, dwelling apartments, etc., are put at the disposal of all with an equal liberality; and this absence of distinction between rich or poor, Frenchmen or foreigners, is the source of a charming cordiality and good will among the workers.

Shall we speak, too, of the richness of the Roscoff fauna? This has become proverbial among zoologists, as can be attested by the 265 of them who have worked at the laboratory. The very numerous and remarkable memoirs that have been prepared here are to be found recorded in the fourteen volumes of the _Archives de Zoologie Experimentale_ founded by Mr. Lacaze Duthiers.

It only remains to express our hope that the aquarium may be soon finished; but before this is done it will be necessary to get possession of that unfortunate little road. After this final victory, Mr. Duthiers in his turn will be able, amid his pupils, to enjoy all those advantages of his work which he has until now offered to others, but from which he himself has gained no benefit.--_La Nature._

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THE MURÆNÆ AT THE BERLIN AQUARIUM.

Of all fish, eels are probably the most interesting, as the least is known of them. Electricians are now examining the animal source of electricity in the electric eel (Gymnotus electricus); zoologists are still searching for the solution of the problem of the generation of eels, of which no more is known than that the young eels are not born alive; and numerous fishing societies are now studying the important question of raising eels in ponds, lakes, etc., that are not connected with the sea.

The annexed cut, taken from the _Illustrirte Zeitung_, is a copy of a drawing by Muetzel, and represents a group of Mediterranean Murænæ (Muræna Helena). This fish attains a length of from 5 ft. to 6 ft., and has a smooth, scaleless body of a dark color, on which large light-yellow spots appear, which give the fish a very peculiar appearance. The pectoral fin is missing, but it has the dorsal and anal fins, which it uses with great ability. Its head is pointed, and its jaws are provided with extraordinarily sharp teeth, which are inclined toward the rear; and at each side of the head it is provided with a gill. The nostrils are on the upper side of the snout, and a second, tubular, pair of nostrils is located near the eyes. The bright eyes have a fierce expression, which makes the fish appear very much like a snake. These fish are ravenous, and devour crabs, snails, worms, and fishes, and if they have no other food, bite off the tails of their brethren. They are caught in eel baskets or cages, and by means of hooks; but they are rather dangerous to handle, as they attack the fishermen and injure them severely.

Since the times of the ancients, Murænæ have been prized very highly on account of their savory flesh. The Romans were great experts at feeding these fish, Vidius Pollio being the master of them all, as he made a practice of feeding his Murænæ with the flesh of slaves sentenced to death. Pliny states that at Cæsar's triumphal entry Hirius furnished six thousand Murænæ. Slaves were frequently driven into the ponds, and were immediately attacked by the voracious fishes, and killed in a very short time.

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METAMORPHOSES OF ARCTIC INSECTS.