editors of the Phil. Mag. and Journal of Science to insert in that journal. Feb. 13, 1836.

"Dear Sir,

H. J. BROOKE.

"Mexico, November 14, 1835.

"I have again examined the mineral you have been so kind as to name Riolite, and have found it to be not a seleniuret of zinc, but a native selenium ore with a variable mixture of sulphoseleniuret of mercury, and seleniurets of cadmium and iron.

I put in a retort 53 grs. which I washed to separate the carbonate of lime as some particles were attached to the sides of the retort, I washed it down with some water, and at the moment many round little lumps of selenium arose to the surface, which was covered with a film of the same, proving that it was not combined. There were sublimed by the distillation 38 grs. of selenium and 11⁄2 of mercury, which was also amalgamated with selenium; and there remained in the retort 10 grs. of a yellow and grey powder.

1. I treated the 10 grs. with muriatic acid, which dissolved the iron and the cadmium, and the selenium was precipitated as a black powder, which amounted to gr.

2. I precipitated the diluted solution (1.) with a small bar of zinc : the grey and voluminous cadmium was easy to be distinguished from the iron both amounted to 14 gr.

3. The iron was dissolved in diluted muriatic acid, and the cadmium in concentrated; and the last was precipitated again with a bar of zinc in a crucible of platinum, to which some cadmium was attached as a silver white metal, and some was precipitated as a dark grey powder, which deposited upon the charcoal at the blowpipe a reddish brown ring.

4. Together with the black powder (1.) I observed another precipitate lighter in colour and heavier, which I separated by washing, and treated with hydrochloromuriatic acid. All was dissolved immediately, and red selenium arose to the surface, which was reduced to selenious acid by the addition of nitric acid: there remained only a melted globule of sulphur. At the same time some sulphate of lime was precipitated, which amounted to 14 gr.

5. I precipitated the last solution with hydrosulphate of ammonia, and I obtained 6 grs. of sulphuret of mercury.

6. The selenium (1.) was put in a little capsule over the lamp in a dark corner of my room with some sulphuric acid, and gave many small flashes of light on the surface of the liquid of the selenious acid which sublimed; I smelled some sulphurous acid, and the decanted solution precipitated red selenium with water; the remaining solution precipitated the same without water; and there was at the bottom selenious acid as a white powder.

As the quantities of mercury and cadmium are variable, because I found more in other specimens, I think this mineral is nothing else than a mixture to which no formula can properly be applied.

In the beginning, when I thought it was a seleniuret of a fixed base, I treated it twice at the blowpipe with some iron and borax, and after washing the charcoal I found both times the next day very small double

rhomboidal, oblique pyramids of seleniuret of iron of a dark grey colour: the iron was dissolved in muriatic acid, and the black selenium was precipitated.

I take profit of this opportunity to let you know that the Herrerite is not a carbonate of tellurium, as it was announced by my pupil, but of zinc and nickel, which gives to it the pretty pistachio and grassgreen colour: it contains also some cobalt; and the apple-green, fibrous, and very soft substance, which accompanies it, and I supposed erroneously to be a species of the preceding, shows to be at the blowpipe an arseniate of nickel.

As soon as I get some pieces of your Culebrite, I will examine it, and give you notice.

ANDREA DEL RIO.

METEOROLOGICAL OBSERVATIONS FOR JANUARY 1836.

REMARKS.

Chiswick - January 1. Snow. 2. Severe frost: slight snow at night. 3. Thawing: cloudy and fine. 4. Cloudy: stormy. 8. Hazy: fine. 9. Frosty. 10. Stormy, with some snow. 11. Overcast: heavy rain. 12. Sharp frost: clear and calm. 13. Frosty cloudy. 14. Cloudy and windy. 15. Heavy rain : clear and windy at night. 16, 17. Clear and frosty. 18. Cloudy and cold. 19. Fine. 20. Frosty haze: overcast. 21. Fine: clear. 22. Slight rain. 23. Boisterous. 24-26. Very fine. 27. Fine: stormy at night. 28. Fine: slight rain windy. 29. Cloudy and cold. 30. Clear and frosty: fine but cold. 31. Rain.

:

The plan which is followed in regard to the meteorological observations made at the Garden of the Horticultural Society, is in accordance with that recommended by Professor Daniell in his excellent Meteorological Essays. A full account of the instruments employed is given by Mr. Booth in vol. vii., p. 97, of the First Series of the Hort. Soc. Transactions. It will be proper, however, to mention such circumstances as are connected with the abstract which appears in the Phil. Mag. and Journal of Science.

The barometer is situated about fourteen feet above the mean level of the Thames, at Chiswick. The observations are taken at 8 A.M., 1 p.m., and 10 P.M. A correction is made for every observation for the capacity of the cistern, the neutral point of the barometer, and the temperature of the mercury; so that the column of mercury is reduced to that which, at a temperature of 32°, would balance the atmosphere. The thermometers indicating the max. and min. of temperature are self-registering, and of Rutherford's construction; they are placed in an open space in the Arboretum, and are protected from the rays of the sun by a sort of umbrella of painted canvas. They are attached to the post which supports the umbrella, a little below the level of the margin of the latter, and about four feet from the ground.

The rain-gauge is made according to Mr. Howard's directions, in his work upon the Climate of London. The quantity is registered every morning, when there is any, at 8 A.M. The direction of the wind is noted at 1 P.M.

Boston.-January 1, 2. Cloudy.

5. Fine. 6. Cloudy. 7, 8. Fine.

3. Cloudy; rain P.M.

4. Cloudy. 9. Cloudy. 10. Cloudy: snow P.M.

11, 12. Cloudy. 13. Fine. 14. Fine: snow melted: stormy night, with rain. 15. Fine: rain P.M. 16, 17. Fine.

20, 21. Cloudy. 22. Cloudy: rain P.M.

18. Cloudy: rain P.M. 19. Fine. 29. Stormy. 24. Fine: rain P.M.

25. Foggy. 26. Cloudy. 27. Fine. 28. Fine: rain P.M. 29. Fine: snow A.M. 30. Cloudy and stormy: snow A.M. 31. Snow.

Meteorological Observations made at the Apartments of the Royal Society by the Assistant Secretary; by Mr. THOMPSON at the Garden of the
Horticultural Society at Chiswick, near London; and by Mr. VEALL at Boston.

Days of
Month.
1836.

Chiswick. Boston. 8 A.M.

London:
Roy. Soc.
9 A.M.

Chisw. Bost.
1 P.M.

London:
Roy. Soc.
9 A.M.

Chisw.

Boston.

30 13

34

38-6

43-4

37-3

Sum

1:79

LONDON AND EDINBURGH

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

APRIL 1836.

LIII. Observations upon the Habits of the Plecotus auritus, or Long-eared Bat. By J. DE C. SOWERBY, Esq., F.L.S.*

A

BOUT the beginning of August last, a living specimen of the Long-eared Bat was given to my children. We constructed a cage for him by covering a box with gauze and making a round hole in the side fitted with a phial cork. When he was awake we fed him with flies introduced through this hole, and thus kept him for several weeks. The animal soon became familiar, and immediately a fly was presented alive at the hole he would run or fly from any part of the cage and seize it in our fingers, but a dead or quiet fly he never would touch. At other times dozens of flies and grasshoppers have been left in his cage, and waking him by their noise, he dexterously caught them as they hopped or flew about, but uniformly disregarded them while they were at rest. The common Blatta, hard Beetles, and Caterpillar he refused, even after he had been induced by their moving to attack them. As we became still more familiar our new friend was invited to join in our evening amusements, to which he contributed his full share by flitting round the room, at times settling upon our persons and permitting us to handle and caress him. He announced his being awake by a shrill chirp,

Read at the first Philosophical Meeting of the Camden Literary and Scientific Institution, January 26, 1836: and now communicated by the

Author.

Third Series. Vol. 8. No. 47. April 1836.

2 E

which was much more acute than that of the Cricket. Now was the proper time for feeding him. I before stated that he only took his food alive: it was also observed that not only was motion necessary, but that generally some noise on the part of the fly was required to induce him to accept it; and this fact was soon discovered by the children, who were entertained by his taking flies from their fingers as he flew by them, before he was bold enough to settle upon their hands to devour his victims. They quickly improved upon their discovery, and by imitating the booming of a bee, induced the bat, deceived by the sound, to settle upon their faces, wrapping his wings round their lips and searching for the expected fly. We observed that if he took a fly while on the wing, he frequently settled to masticate it; and when he had been flying about a long time he would rest upon a curtain, pricking his ears and turning his head in all directions, when if a fly were made to buzz, or the sound imitated, he would proceed directly to the spot, even on the opposite side of the room, guided, it should appear, entirely by the ear. Sometimes he took his victim in his mouth, even though it was not flying; at other times he inclosed it in his wings, with which he formed a kind of bag-net; this was his general plan when in his cage, or when the fly was held in our fingers or between our lips.

From these observations I should conclude that many of the movements of the Bat upon the wing are directed by his exquisite sense of hearing. May not the sensibility of this organ be naturally greater in those animals whose organs of vision are too susceptible to bear daylight, when those organs, from their nature, would necessarily be of most service? such as the cat, who hunts much by the ear, and the mole, who feeding in the dark recesses of his subterranean abode is very sensible of the approach of danger and expert in avoiding it. In the latter case large external ears are not required, because sound is well conveyed by solids and along narrow cavities. In the cases of many bats and of owls the external ears are remarkably developed. Cats combine a quickness of sight with acute hearing; they hunt by the ear, but they follow their prey by the eye. Some bats are said to feed upon fruits; have they the same delicacy of hearing, feeling, &c. as others?