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Dall; 5. T.? galtensis, Bill., = minor, Dall; 6. T. ohioensis, Meek ; 7. T. Dalli, Dav. & King ; 8. T. wisbyensis, Dav. & King.

Genus 2. Monomerella, Billings (1871). Sp. 1. M. prisca, Bill. ; 2. M. Walmstedti, Dav. & King ; 3. M. Lindströmi, Dav. & King; 4. M. orbicularis, Bill.

Genus 3. Dinobolus, Hall (1871). Sp. 1. D. Conradi, Hall ; 2. D. Davidsoni, Salt.; 3. D. canadensis, Bill.; 4. D. transversus, Salt. ; 5. D. Woodwardi, Salt. ; 6. D. magnificus, Bill. ; 7. D. Schmidti, sp. n.

The authors further discuss the characters of Professor Hall's Lingulops Whitfieldi, which they regard as in some respects intermediate between the Lingulidæ and Trimerellidæ, and describe under the name of Chelodes Bergmani a fossil sent to them by Dr. Lindström under the impression that it was a Trimerellid. They indicate its points of resemblance to Trimerella, but think that it really belongs to the section of the Coelenterata represented by Calceola and Goniophyllum. The fossil is from the isle of Gothland, and was obtained from a formation equivalent to the Aymestry limestone.

X. Intelligence and Miscellaneous Articles.
PERMANENT ICE IN A MINE IN THE ROCKY MOUNTAINS.

BY R. WEISER, OF GEORGETOWN, COLORADO.
G

rocks found in some of our silver-mines in Clear Creek Co., Colorado. I will first give a statement of the facts in the case, and then a theory for their explanation.

There is a silver-mine high up on McClellan Mountain, called the “ Stevens Mine.” The altitude of this mine is 12,500 feet. At the depth of from 60 to 200 feet the crevice matter, consisting of silica, calcite, and ore, together with the surrounding wall-rocks, is found to be in a solid frozen mass. McClellan Mountain is one of the bighest eastern spurs of the Snowy Range; it has the form of a horseshoe, with a bold escarpment of felspathic rock near 2000 feet high, which in some places is nearly perpendicular. The Stevens Mine is situated in the south-western bed of the great horseshoe ; it opens from the north-western. A tunnel is driven into the mountain on the lode, where the rock is almost perpendicular. Nothing unusual occurred until a distance of some 80 or 90 feet was made; and then the frozen territory was reached, and it has continued for over 200 feet. There are no indications of a thaw summer or winter; the whole frozen territory is surrounded by hard massive rock, and the lode itself is as hard and solid as the rock. The miners being unable to excavate the frozen material by pick or drill to get out the ore (for it is a rich lode, running argentiferous galena from 5 to 1200 ounces to the ton), found the only way was to kindle a large wood fire at night against the back end of the tunnel and thus thaw the frozen material, and in the morning take out the disintegrated ore.

This has been the mode of mining for more than two years. The tunnel is over 200 feet deep, and there is no diminution of the frost; it seems to be rather increasing. There is, so far as we can see, no opening or channel through which the frost could possibly have reached such a depth

the

from the surface. There are other mines in the same vicinity in a like frozen state.

From what we know of the depth to which frost usually penetrates into the earth, it does not appear probable that it could have reached the depth of 200 feet through the solid rock in the Stevens. Mine, nor even through the crevice matter of the lode, which, as we have stated, is as hard as the rock itself. The idea, then, of the frost reaching such a depth from the outside being utterly untenable, I can see no other

way
than to fall back

upon Glacial era of the Quaternary. Evidences of the Glacial Period are found all over the Rocky Mountains. Just above the Stevens Mine there are the remains of a moraine nearly a mile long, and half a mile wide. The débris of this moraine consists of small square and angular stones, clearly showing that they have not come from any great distance. And just over the range, on the Pacific slope, there are the remains of the largest moraine I have ever seen, consisting of felspathic boulders of immense size. I conclude, therefore, that it was during that period of intense cold that the frost penetrated so far down into these rocks, and that it has been there ever since, and bids fair to remain for a long time to come.-Silliman's American Journal, December 1874.

ON THE MIXTURE OF COLOURS IN BINOCULAR VISION.

BY W. VON BEZOLD*. The Author has succeeded in clearing up and reconciling the divergent observations of different observers on the mixed colours produced when the two eyes receive light of different colours. Some, as Dove or Ludwig, assert most positively that it is possible to obtain a combined colour by the binocular fusion of two images of different colours; while Franke, Helmholtz, and others advance precisely the contrary.

According to the Author, the combined tint is obtained when, with one and the same accommodation, the differently coloured surfaces are both at the distance of distinct vision. When this is not the case, there is a struggle between the two visual fields, and one or the other prevails.-Bibliothèque Universelle, Archives des Sciences,

p.

184. EXPERIMENTAL STUDIES ON THE ELECTRICAL RESISTANCE OF

METALS AND ITS VARIATION UNDER THE INFLUENCE OF TEMPERATURE. BY RENÉ BENOIT.

Resuming the important question of the electric conductivity of metals, M. Benoit first measured very accurately the specific resistance of a number of them at 0° C. For this he operated comparatively with two different methods—that of the differential galvanometer, and that of the Wb stone bridge; and he made numerous determinations on various specimens of each metal. The following Table contains the means of all the results, which are referred to the two units now most generally adopted for the measurement of

* Pogg. Ann. Jubelband, p. 585. † A thesis presented to the Paris Faculty of Sciences,

No 202,

conductivities, viz. the British-Association unit, or ohm, and the Siemens unit.

[blocks in formation]

rom the surface. There are other mines in the same vicinity in a ke frozen state.

From what we know of the depth to which frost usually peneates into the earth, it does not appear probable that it could have eached the depth of 200 feet through the solid rock in the tevens Mine, nor even through the crevice matter of the lode,

hich, as we have stated, is as hard as the rock itself. The idea, nen, of the frost reaching such a depth from the outside being tterly untenable, I can see no other way than to fall back upon the lacial era of the Quaternary. Evidences of the Glacial Period re found all over the Rocky Mountains. Just above the Sterens fine there are the remains of a moraine nearly & mile long, and aalf a mile wide. The débris of this moraine consists of small quare and angular stones, clearly showing that they have not come rom any great distance. And just over the range, on the Pacific ope, there are the remains of the largest moraine I have ever een, consisting of felspathic boulders of immense size. I com

ude, therefore, that it was during that period of intense cold that ne frost penetrated so far down into these rocks, and that it has een there ever since, and bids fair to remain for a long time to ome. -Silliman's American Journal, December 1874.

Pare silver, annealed..
Copper, annealed
Silver 0:75, annealed
Pure gold, annealed
Aluminium, annealed
Magnesium, cold-beaten
Pure zinc, annealed at 350°
Pure cadmium, cold-beaten
Brass, annealed*
Steel, annealed
Pure tin
Aluminium bronze, annealedt
Iron, annealed
Palladium, anvealed
Platinum, annealed
Thallium
Pure lead
German silver, annealed I.

0.0154 0.0171 0.0193 0.0217 0-0309 0.0423 0.0565 0.0685 0.0691 0.1099 0:1161 0.1189 0:1216 0.1384 0·1575 0.1831 0.1985 0.2654 0.9564

0.0161 0.0179 0.020) 0·0227 0·0324 0.0443 0·0591 0.0716 0.0723 0:1149 6.1214 0:1243 0.1272 0·1447 0.1647 0:1914 0.2075 0.2775 1.0000

71 49.7 36-4 27.5 22-5 22:3 14.0 13:3 13.0 12:7 11.) 9.77 8.41 7.76 5.80 1.61

Pure mercury.

ON THE MIXTURE OF COLOURS IN BINOCULAR VISION.

BY W. VON BEZOLD*. The Author has succeeded in clearing up and reconciling the ivergent observations of different observers on the mixed colours roduced when the two eyes receive light of different colours. bme, as Dove or Ludwig, assert most positively that it is possible obtain a combined colour by the binocular fusion of two images different colours; while Franke, Helmholtz, and others advance ecisely the contrary. According to the Author, the combined tint is obtained when, h one and the same accommodation, the differently coloured sures are both at the distance of distinct vision. When this is not

case, there is a struggle between the two visual fields, and one the other prevails. --Bibliothèque Universelle, Archives des Sciences, 202, p. 184.

From the third column, which gives the specific conductivities of these metals referred to that of silver, it is seen that the results ohtained by the author differ but little from those which have been given by other experimenters.

The diminution undergone by the electric conductivity of the metals with rise of temperature was the essential aim of M. Benoit's researches. This influence of temperature, already remarked by Davy, was studied by Ed. Becquerel, who measured it up to 100°, by Matthiessen, who followed it as far as 200°, and by other physicists. M. Benoit has set himself the task of studying this variation of conductivity within the most extended limits of temperature. The conducting wire on which he operated was wrapped spirally round a cylindrical support of pipeclay, enclosed in a muffle which was immersed in a bath of a volatile liquid heated by aid of a Perrot furnace. The liquid was water, mercury, sulphur, or cadmium, by means of which constant temperatures were obtained of 100°, 360°, 440°, and 860o. Moreover a great number of experiments were made above 360° by aid of a mercury bath, the temperature of which was regulated. These measurements were corrected for the dilatation.

Plates annexed to the memoir give the graphic representation of the results obtained. They show that the increase of the resistance follows a regular. course which continues, probably, for all the metals, as for tin, lead, and zinc, as far as their melting-pointę.

ERIMENTAL STUDIES ON THE ELECTRICAL RESISTANCE OF ETALS AND ITS VARIATION UNDER THE INFLUENCE OP TENGRATURE.

BY RENÉ BENOITt. esuming the important question of the electric conductivity of ls, M. Benoit first measured very accurately the specific resistof a number of them at 0° C. For this he operated comparawith two different methodsthat of the differential galvanor, and that of the Wheatstone bridge; and he made numerous minations on various specimens of each metal. The following contains the means of all the results, which are referred to k'o units now most generally adopted for the measurement of

* From the wiredrawers : copper 64.2, zinc 33:1, lead 0:4, tin 0:4.
† Copper 90, aluminium 10. I Copper 50, nickel 25, zinc 25.

Fusion is in general accompanied, as we know from the researches of

* Pogg. Ann. Jubelband, p. 585.
A thesis presented to the Paris Faculty of Sciences.

This augmentation varies, too, a great deal, from one metal to another. We remark that tin, thallium, cadmium, zinc, lead, are found together towards the upper part : at about 200° and 230° their resistance has doubled. Still above them are found steel and iron : the resistance of the latter has doubled at 180°, quadrupled at 430°, at 860o is about nine times as great as at zero.

Palladium and platinum, on the contrary, approach the axis of the temperatures ; it is only in the vicinity of 4000 and 450° that the augmentation has acquired a value equal to that of the primitive resistance. Gold, copper, silver, form an intermediate group. It may therefore be said generally that, the less elevated the fusing-point of a metal, the more rapidly does its conductivity diminish : iron and steel form an exception to this law. In alloys the variation is always less than in the metals which constitute them. In certain of them (German silver for example) it is very slight; and this renders them valuable for the construction of standards and resistance-coils. Approximately, it is in the metals in which the resistance is greatest that its increase, under the influence of heat, is relatively the most rapid. The slight differences of composition which alter so profoundly the absolute resistance, have but a feeble influence on the relative value of its augmentation by rise of temperature.Bibliothèque Universelle, Archives des Sciences Phys. et Nat., vol. li. pp. 284–287. ON THE CONSERVATION AND THE PROPERTIES OF A PLATE OF PAL

LADIUM SATURATED WITH HYDROGEN BY ELECTROLYSIS.
R. BÖTTGER*.

The Author has found that it is only after being heated to redness that a plate of palladium, charged with hydrogen by electrolysis, loses the hydrogen which it held by occlusion. This is readily ascertained by immersing the plate in a solution of ferrideyanide of potassium. In fact, as long as hydrogen is still present at the surface of the palladium, reduction of the ferridcyanide into ferrocyanide is observed, which is easily recognized by means of the properties of the salts of protoxide of iron.

There are also other metals which thus absorb electrolytic hydrogen--as nickel, zinc, and cobalt.

When a plate of palladium is coated with palladium-black, it becomes saturated with hydrogen much more rapidly. If when thus saturated it is wrapped in gun-cotton, the latter explodes at the end of a few seconds, and the plate burns during five or six minutes with a flame of feeble brightness.

A plate of palladium charged with hydrogen and left in the air, loses in time the gas occluded. Placed under water deprived of air, under absolute alcohol, or ether, it loses at first a part of its hydrogen with effervescence, but retains the rest without apparent change.-Bibliothèque Universelle, Archives des Sciences, vol. li. p. 185. M. L. de la Rive, by a sudden and very great diminution of the conductivity; nevertheless bismuth and antimony form an exception, and become, on the contrary, better conductors on melting.

* Pogg. Ann. Jubelband, p. 150.

BY

[graphic]

Intelligence and Miscellaneous Articles. nis augmentation varies, too, a great deal, from one metal to anher. We remark that tin, thallium, cadmium, zinc, lead, are und together towards the upper part : at about 2009 and 230° their sistance has doubled. Still above them are found steel and iron : e resistance of the latter has doubled at 180°, quadrupled at 430%

, 860o is about nine times as great as at zero. Palladium and atinum, on the contrary, approach the axis of the temperatures;

is only in the vicinity of 400° and 450° that the augmentation as acquired a value equal to that of the primitive resistance. Gold, opper, silver, form an intermediate group. It may therefore be aid generally that, the less elevated the fusing-point of a metal, the nore rapidly does its conductivity diminish : iron and steel form un exception to this law. In alloys the variation is always less han in the metals which constitute them. In certain of them

German silver for example) it is very slight; and this renders Chcm valuable for the construction of standards and resistance-coils. Approximately, it is in the metals in which the resistance is greatest that its increase, under the influence of heat, is relatively the most rapid. The slight differences of composition which alter so profoundly the absolute resistance, have but a feeble influence on the relative value of its augmentation by rise of temperature.--Bibliothèque Universelle, Archives des Sciences Phys. et Nat., vol. li.

pp. 284-287.
ON THE CONSERVATION AND THE PROPERTIES OF A PLATE OF PAL-

LADIUM SATURATED WITH HYDROGEN BY ELECTROLYSIS.
R. BÖTTGER *

The Author has found that it is only after being heated to redness
hat a plate of palladium, charged with hydrogen by electrolysis,
oses the hydrogen which it held by occlusion. This is readily
scertained by immersing the plate in a solution of ferrideyanide of
otassium. In fact, as long as hydrogen is still present at the sur-
ce of the palladium, reduction of the ferrideyanide into ferro-
"anide is observed, which is easily recognized by means of the
operties of the salts of protoxide of iron.
There are also other metals which thus absorb electrolytic hy-
ogen-as nickel, zinc, and cohalt.
When a plate of palladium is coated with palladium-black

, it omes saturated with hydrogen much more rapidly

. If when s saturated it is wrapped in gun-cottori, the latter explodes at

end of a few seconds, and the plate burns during five or six utes with a flame of feeble brightness

.
plate of palladium charged with hydrogen and left in the air,
s in time the gas occluded. Placed under water deprived of
under absolute alcohol, or ether, it loses at first a part of its
ogen with effervescence, but retains the rest without apparent
ge.--Bibliothèque Universelle, Archives des Sciences, vol. li. p. 185.

de la Rive, by a sudden and very great diminution of the conductivity;
theless bismuth and antimony form an exception, and become, on the
iry, better conductors on melting.
ogg. Ann. Jubelband, p. 150.

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