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The ladies did not always hawk on foot; and a picture in the manuscript, known as Queen Mary's Psalter, which we copy here, gives an interesting group of a party on horseback, consisting of two ladies following the sport, attended by a gentleman. Their game is

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here water-fowls, and it was still en rivière. As it will be seen, instead of dogs to rouse the game, they have here a man, or a lad, who is employed to frighten them. It may be remarked, that, in the early Anglo-Saxon manuscripts, wherever a hawking scene is introduced, it is always laid on the bank of a river.

It will be seen in this cut, as well as in a former cut in the present chapter, that, as I said before, the ladies, when they rode on hunting, sat upon the horse astride. In another manuscript in the British Museum (MS. Reg., 20 D. I), written in the fourteenth century, apparently towards the south of France, the ladies appear all riding astride in men's saddles.*

There were other methods of rousing the water-fowl, one of which was by the beating of a tabor. An English chronicler of the

* It may be well here to point out a rather important ERRATUM in the last chapter of WOMANKIND (The STUDENT, No. XIII., p. 20), where the picture of the Duchess of Burgundy entering Paris has been accidentally reversed in the engraving, so that the ladies appear seated on a different side of the horse from the original, where they are, as in every other bona fide example of mediæval female equestrianism I have seen, seated on the right side, with their left hand to the horse's head.

twelfth century, Radulphus de Diceto, tells an anecdote of a youth belonging to the household of the Bishop of London, who went hawking along the river for teal, and rose one "by the sound of that instrument, which is called by those who hawk on the banks of the rivers a tabor" (juxta sonitum illius instrumenti quod a ripatoribus vocatur tabur). This use of the tabor was so common, and lasted

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during so long a period, that we see a picture of men hawking with the tabor among the misereres, or carved seats, in the cathedral of Gloucester, which are of the fifteenth century; and ladies hawking with the tabor are introduced among the illuminations of a manuscript in the fourteenth century, in the British Museum (MS. Reg. 10 E. IV.), of which we give the part representing the damoiselle raising the game in the accompanying cut.

The hawking season began with the month of August, and during the early part of that month appears to have been confined to partridges, at least, so says the “ Ménagier de Paris ”—and the time of the day recommended for the sport was from very early in the morning to tierce, or nine o'clock. The feudal ladies were early risers. In the month of July, we are told, the heat was too great. The partridge was an especially favourite bird with the ladies to hawk. In the middle of August the quail came in, and the two following months appear to have been the busiest of the year. After the end of September, when partridges and quails began to fail, the hawking became more general and indiscriminate, and the ladies were allowed to "fly” at almost anything in the shape of a bird, including fieldfares, thrushes, and even magpies and jays.

THE RELATION OF HYDROGEN TO PALLADIUM.

MR. GRAHAM'S RESEARCHES.

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THE “Intellectual Observer” for July, 1867, contained an account of Mr. Graham's researches on the absorption and dialytic separation of gases by colloid septa.

In continuation, Mr. Graham has solved many of the more difficult and intricate questions that presented themselves during the conduct of the earlier work.

It will be necessary briefly to recapitulate the results already given. In all cases where it was necessary to examine the

passage

of
gas

into vacuum or to extract gas from the metal that formed the subject of experiment, Mr. Graham availed himself of Dr. Sprengel's mercurial exhauster, a falling stream of mercury from A produced a perfect vacuum in any receiver connected with the lateral arm X, the gas or air extracted being delivered at R.

To select a typical ex

periment, it will be remembered that when a palladium tube is rendered vacuous by the mercurial exhauster, and heated in an atmosphere of coal gas, which is a complex mixture of gases, free hydrogen alone

passes through the metal; this penetration of gas was explained by the fact that palladium absorbs or “occludes" many hundred times its volume of hydrogen gas.

It will also be remembered that all metals, especially the colloid ones, i.e. those possessing the crystalline character in the lesser degree, appear to select each its own gas, silver occluding oxygen, iron both carbonic oxide and hydrogen, gold nitrogen.

The fact that iron occluded hydrogen led to the examination or meteoric iron, which experiment proved actually to contain hydrogen.

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This fact possesses peculiar significance, and will be alluded to further on.

In the old experiments the metallic palladium was charged with hydrogen by simple heating, and slow cooling in an atmosphere of gas, it was, however, found that by placing the metal in a voltameter, and connecting it with the zinc pole of a battery, and thereby evolving hydrogen on its surface, imparted both a higher charge, and gave less capricious results than in the dry method of charging. Thus merely to give the results of numerous experiments :Hammered palladium occluded

655 volumes Palladium by electro deposition from the chloride, occluded

982:14 This latter experiment, representing by weight : Palladium

99.277 Hydrogen

0.0073

•723

1.0020 grms

100.000

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or an approximation to single equivalents PdH. Then with regard to the penetration of palladium by hydrogen, Mr. Graham remarks :-"I am inclined to conclude that the passage of hydrogen through a plate of metal is preceded by the condensation or occlusion of the gas, but the rapidity of penetration is not in proportion to the volume of gas occluded; otherwise palladium would be much more permeable at a low than at a high temperature.”

By actual experiment at the temperature about the melting point of gold, hydrogen passed through a palladium tube one millimetre in thickness, at the rate of 105.8 cubic centimetres in five minutes, and as the external surface of the palladium was 0.0053 square metre, the passage was at the rate of 3992-22 cubic centimes per minute for a square metre. With the same tube, carbonic acid gas penetrated with one-twenty-thousandth part of the rate of hydrogen.

And though experiment proved that the quantity of hydrogen held by the metal at this high temperature was too small to be appreciated, Mr. Graham nevertheless considers it to be present, and to travel through the metal by a kind of rapid cementation, indicating the extreme mobility of the hydrogen. The first attempts to arrest hydrogen in its passage through the red-hot metal were made by transmitting hydrogen gas through a metal tube of palladium with a vacuum outside, rapidly followed by a stream of carbonic acid, in which the metal was allowed to cool. When the metal was afterwards examined in the usual way, no hydrogen could

be found in it. The short period of exposure to the carbonic acid seems to have been sufficient to dissipate the gas. But on heating palladium foil red-hot in a flame of hydrogen gas, and suddenly cooling the metal in water, a small portion of hydrogen was found locked up in the metal.

in the metal. A volume of metal amounting to 0:062 c.c. gave 0.080 c.c. of hydrogen; or, the gas, measured cold, was 1.306 times the bulk of the metal. This measure of gas would amount to three or four times the volume of the metal at a red heat. Platinum treated in the same way appeared also to yield hydrogen, although the quantity was too small to be much relied upon, amounting only to 0·06 volume of the metal. The permeation of these metals by hydrogen appears, therefore, to depend on absorption, and not to require the assumption of anything like porosity in their structure. In the former paper, Mr. Graham says :

- Whatever may

be thought of the physical condition of the hydrogen in the palladium, it is certainly not present as a gas."

The second paper (communicated to the Royal Society, January 14th, 1869) details Mr. Graham's views, and, as will be seen, developes results of great beauty. Chemists have long maintained that hydrogen was merely the vapour of a highly volatile metal, we may therefore be prepared to admit that "palladium with its occluded hydrogen is simply an alloy of this volatile metal in which the volatility of the one element is restrained by its union with the other, and which owes its metallic aspect equally to both constituents.”

As Mr. Graham proposes the name hydrogenium for this metal, we must examine in detail the evidence by which he arrives at a result of such extreme importance.

Obviously, the first point to ascertain is the density of the alloy. Although the specific gravity of the palladium, when charged with 900 volumes of hydrogen, is perceptibly lowered, the change cannot be measured in the ordinary way, by immersion in water, owing to the fact, that contact with the liquid gives rise to a continuous evolution of bubbles of hydrogen gas. Fortunately, however, the palladium, when charged with hydrogen, is actually and permanently expanded to a greater extent than if heated to redness, this expansion may be easily measured, and the difference of density found by calculation. The palladium (in the form of wire) was employed in the following experiments, and the charge imparted in the usual way, by evolving hydrogen on the surface of the water, in a galvanometer, containing dilute acid.

Then the wires were stretched by a moderate weight, and accurately measured before and after charging with hydrogen, extra

VOL. III.-NO. II.

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