1. Stiblite. This occurs in crusts upon antimony and quartz, and in pseudomorphs after antimonite, the remains of whose crystals may generally be seen occupying the centres of the pseudomorphs. They are opaque, of a pale ochre-yellow color, and possessed of a glimmering lustre. In a closed tube they yield water; before the blowpipe are not reduced, but form a stain on charcoal.

2. Senarmontite.-This exists in small, nearly transparent, octahedral crystals. Before the blowpipe, melts easily; on charcoal, forms a thick white coating; and in the reducing flame gives metallic antimony. In the closed tube it wholly sublimes. It dissolves readily in chlorhydric acid, the solution yielding a white precipitate on dilution with water.

3. Kermesite.-Occurs in minute acicular crystals and in com. pact bundles of diverging fibres. Color cherry-red. Before the blowpipe, melts; depositing a sublimate of antimonious acid. Soluble in chlorhydric acid with extrication of sulphuretted hydrogen. When treated in powder with caustic potassa, its color changes to yellow, after which it is taken into solution.

Eudialyte in Arkansas.-I found this mineral in 1861 at Magnet Cove, in imperfect rounded crystals, imbedded in feldspar, and associated with ægirine, the three belonging to the extensive elæolitic rock of that remarkable region. At first, I took it for corundum, its color being a rich crimson, varying to peachblossom red. Its hardness, however, was discovered to be rather under 6. Before the blowpipe it melted into a greenish scoria, and when in powder promptly gelatinized in chlorhydric acid.

Ægirine also occurs at the same locality in loose crystals in

the soil,

Tungsten at Chesterfield, Ms.-A specimen of this tin-accompa nying species has for some years been in my collection, coming from the celebrated green and red tourmaline vein of Chesterfield. It is imbedded in albite and associated with tourmalines. It was in close proximity to minute crystals of cassiterite, a species now frequently found in the granite of the adjoining towns of Goshen and Norwich.

Amherst, Jan. 7, 1864.

SCIENTIFIC INTELLIGENCE.

I. PHYSICS AND CHEMISTRY.

1. On the spectrum of carbon.—ATTFIELD has examined the spectrum of carbon as observed in various flames containing this element, and in the light of the electric spark passed through dilute carbonic oxyd and bisulphid of carbon. Swan observed in 1856 that all hydrocarbon flames give four groups of rays, which are respectively faint yellow, light green, bright blue, and rich violet. The author concluded that these bands must arise from incandescent carbon vapor. The spectrum of a mixture of coal gas and oxygen was brilliant and well defined. The yellow-green band was found to consist of six lines; the green band of five; the blue of five, and the violet band of two with a faint hair line between. The spectrum of cyanogen gave-as stated long since by Draper-a splendid series of bands which became still more distinct and brilliant on feeding the flame with oxygen. By direct comparison it was easily shown that the cyanogen spectrum contains the same lines as that of coal gas, together with a very distinct and complex nitrogen spectrum. Rarefied cyanogen gave precisely the same spectrum on passing electric discharges through the tube. A tube containing a trace of olefiant gas gave a spectrum identical with that of a hydrocarbon burning in air. The flames of carbonic oxyd and bisulphid of carbon give continuous spectra, but when small quantities are ignited in tubes by the electric discharge, brilliant and sharp spectra are obtained which exhibit the four groups of bands above described. The author concludes that these bands form the spectrum of carbon, and as the blue band is the brightest, be explains in this manner the blue color of many flames. The "blue heat" of a Deville's furnace is doubtless a case in point.-Journal of Chem. Soc., [2], i, 97.

W. G.

2. On the optical distinction between hypermanganic acid and compounds of sesquioxyd of manganese.-HOPPE-SEYLER has found that a solution of hypermanganic acid exerts a powerful absorption upon green and green-yellow rays. A solution of phosphate of sesquioxyd of manganese exhibits the same action. If, however, the solution of this salt is diluted more and more, the absorption in the middle of the spectrum gradually disappears without the appearance of definite bands, while dilute solutions of hypermanganic acid exhibit five distinct absorption bands, of which the first, reckoning from the red, lies beyond D, the second dark band between C and b (sic), the third, also very dark, upon E extending to b, the fourth between band F, and the fifth and weakest upon F. Sesquichlorid and sulphate of sesquioxyd of manganese exhibit the same action as the phosphate, except that there is here an absorption also in the blue and violet. The solution obtained by Crum's test exhibited the five absorption bands very clearly. Hence it appears that Rose was in error in considering this solution to contain sesquioxyd.— Journal für prakt. Chemie, xc, 303.

3. On the action of light upon nitro-prussid of sodium.-ROUSSIN has proposed a method of determining the chemical intensity of light which is based upon the decomposition produced in a solution of nitro-prussid

of sodium mixed with sesquichlorid of iron. The author recommends a solution containing two parts of this nitro-prussid, two of dry sesquichlorid of iron, and ten of water. The solution is to be filtered and kept in a bottle covered with black paper. An exposure of a few minutes to solar light is sufficient to communicate to this liquid an intense blue tint with an abundant precipitate of prussian blue. The author proposes to measure the chemical intensity of light by determining the density of the normal solution by means of an areometer before and after insolation, the temperature being in each case supposed to be the same. It seems not impossible that this process may contain the germ of a valuable method of investigation, but no experimental data are given by which to judge of its value.-Les Mondes, March, 1864, 415.

W. G.

4. On the barometer, as an indicator of the earth's rotation, and the sun's distance; by PLINY EARLE CHASE.-The existence of daily barometric tides has been known for more than a hundred and fifty years, but their cause is still a matter of dispute. It is evident that they cannot be accounted for by variations of temperature, for, 1, their regularity is not perceived until all the known effects of temperature have been eliminated; 2, they occur in all climates, and at all seasons; 3, opposite effects are produced at different times, under the same average temperature. Thus at St. Helena, the mean of three years' hourly observation gives the following average barometric heights:

From Oh to 12h 28-2801 in.

From 18h to 6h 28-2838 in. 46 6h to 18h 28.2784"

66 12h to Oh 28-2861 " The upper lines evidently embrace the coolest parts of the day, and the lower lines the warmest. Dividing the day in the first method, the barometer is highest when the thermometer is highest; but in the second division the high barometer prevails during the coolest half of the day.

On account of the combined effects of the earth's rotation and revolution, each particle of air has a velocity in the direction of its orbit, varying at the equator from about 65,000 miles per hour, at noon, to 67,000 miles per hour, at midnight. The force of rotation may be readily compared with that of gravity by observing the effects produced by each in twenty-four hours, the interval that elapses between two successive returns of any point to the same relative position with the sun. The force of rotation producing a daily motion of 24,895 miles, and the force of terrestrial gravity a motion of 22,738,900 miles, the ratio of the former to the latter is 29, or 00109. This ratio represents the proportionate elevation or depression of the barometer above or below its mean height that should be caused by the earth's rotation, and it corresponds very nearly with the actual disturbance at stations near the equator. From Oh. to 6h. the air has a forward motion greater than that of the earth, so that it tends to fly away; its pressure is therefore diminished, and the mercury falls. From 6h. to 12h. the earth's motion is greatest; it therefore presses against the lagging air, and the barometer rises. From 12h. to 18h. the earth moves away from the air, and the barometer falls; while from 18h. to 24h. the increasing velocity of the air urges it against the earth, and the barometer rises.

1 From the Proceedings of the American Philosophical Society. AM. JOUR. SCI.-SECOND SERIES, VOL. XXXVII, No. 111.—MAY, 1864.

If the force of rotation at each instant be resolved into two components, one in the direction of the radius vector, and the other parallel to the earth's orbit, it will be readily perceived that whenever the latter tends to increase the aerial pressure, the former tends to diminish it, and vice versa. Let B-1 the height of the barometer at any given instant; M=the mean height at the place of observation; 0-90° the hour angle; c=the earth's circumference at the equator; t=24 hours; g-the terrestrial gravity; the latitude and a simple integration

gives the theoretical formula, B=M(1+

sin cos cos l 2C

R3

gt2

This formula gives a maximum height at 9h. and 21h. and a minimum at 3h. and 15h. The St. Helena observations place the maximum at 10h. and 22h. and the minimum at 4h. and 16h.: an hour later in each instance than the theoretical time. This is the precise amount of retardation caused by the inertia of the mercury, as indicated by the comparisons with the water barometer of the Royal Society of London.

Aerial currents, variations of temperature, moisture, and centrifugal force, solar and lunar attraction, the obliquity of the ecliptic, and various other disturbing causes, produce, as might be naturally expected, great differences between the results of theory and observation. But by taking the grand mean of a series of observations, sufficiently extended to balance and eliminate the principal opposing inequalities, the two results present a wonderful coincidence.

According to our formula, the differences of altitude at 1, 2, and 3 hours from the mean, should be in the respective ratios of 5, 966, and 1. The actual differences, according to the mean of the St. Helena observations, are as follows:

The mean of the above differences varies from the theoretical mean less than go of an inch. If we take the mean of the ratios, instead of the ratios of the means of the observed differences, the coincidence is still more striking.

C

gt2

represents the effective ratio of an entire day. But there is in each day a

half day of acceleration, and a half day of retardation, and the ratio for each half

C

gta 2C

=

The calculated time for the above observed means differs less than 20" from the actual time.

The varying centrifugal force to which the earth is subjected by the ellipticity of its orbit, must, in like manner, produce annual tides. The disturbing elements render it impossible to determine the average monthly height of the barometer, with any degree of accuracy, from any observations that have hitherto been made. We may, however, make an interesting approximation to the annual range, still using the St. Helena records, which are the most complete that have yet been published for any station near the equator. Comparing the mean daily range, as determined by the average of the observations at each hour, with the mean yearly range, as determined by the monthly averages, we obtain the following results:

The approximate estimates of the solar distance are based on the following hypothesis:

=

Let e effective ratio of daily rotation to gravity.

a=arc described by force of rotation in a given time t.

r-radius of relative sphere of attraction, or distance through which a body would fall by gravity, during the disturbance of its equilibrium by rotation.

Aarea described by radius vector in time t.

Let e', a', r', A', represent corresponding elements of the annual revolution. Then,

A: A': ar : a' r' :: e2: ela

But the forces of rotation and revolution are so connected, that a differs but slightly from a'.

It may be interesting to observe how nearly r (22,738,900 m.) corres

Ꭰ

ponds with Kirkwood's value of (24,932,000 m.). A more thorough

comprehension of all the various effects of gravity and rotation on the atmosphere, would probably lead to modifications of our formulæ that would show a still closer correspondence.