2. Scientific Expedition from Williams College.-The scientific expedition from Williams College, consisting of five members of the present senior class, under the charge of H. M. Myers, which left the States last November for the purpose of making explorations and collections in Central America, returned from that country in March, having successfully accomplished the objects proposed. The party spent some time upon the elevated plain of Comayagua, in Spanish Honduras, where they found the climate. most salubrious. One of the immediate results of the expedition is a fine addition to the cabinets of Williams College. The ornithological specimens secured, taken in connection with those added to the museums by the expedition to South America, in 1867, give the college a most valuable collection of tropical birds. Among the additions to the archæological department are two interesting statues exhumed at Corosal, in British Honduras, ninety miles south of Belize. The work upon these images, cut from limestone rock, is quite finely executed; and being still in a good state of preservation, they are valuable and interesting relics, marking the advances in civilization made prior to the occupation of the country by the Spaniards. Although the table-lands and the Pacific coast of these Central American States have been frequently visited by collectors, the low coast-lands of the northern slope have been almost entirely passed by on account of their unhealthfulness. Collections from these comparatively new fields are especially valuable; moreover, the richness of the fauna and flora offer every inducement to the naturalist. It was upon these lowlands that the Williams College party made their largest collections.

3. Description of a Tide-Gauge for cold climates; by JOHN M. BATCHELDER, of Cambridge, Mass.-This instrument is intended for registering the height of the tide at stations where the float and box commonly used are liable to be obstructed by ice.

A strong iron tube, about four inches in diameter, is firmly bolted to a wharf or pile. It is open at the top, and has at the lower end a nipple to which an India-rubber bag is fastened, the length of the tube being sufficient to allow the elastic bag to be always submerged at the lowest stage of the tide.

The bag is supported by a suitable shelf, or cage, and is filled with glycerine, which is poured in at the top of the tube. When in this condition the glycerine rises and falls within the iron tube in proportion to the varying height and pressure of the column of water above the rubber bag, the difference in the height of the two columns being in proportion to the difference of the specific gravity of the water and the glycerine. The parts above described insure protection from floating ice, and prevent congelation within the iron tube.

A copper tube, about three inches in diameter, closed at the bottom, and open at the top, is placed within the iron tube, and floats in the glycerine: if left free it would rise and fall with the changing level of this liquid. The length of the central tube is a little greater than the whole range of the tide.

Near the upper end of the outer tube, there are three spiral springs, fixed at the top and united at the bottom by a plate or disk, from which the central copper tube is suspended. From a stem fixed to the center tube or float, and moving with it, a string or chain leads over a single pulley, and gives horizontal motion to the pencil carriage of the recording apparatus.

The distance that the central tube is to move, vertically, is adjusted to agree with the required range of the pencil upon the record paper, by placing within it suitable weights.

As the glycerine falls or rises in the annular space between the iron tube and the central float, the spiral spring at the top is more or less extended, the extension being uniform on account of the cylindrical form of the float.

It is not necessary that the India-rubber bag be enclosed in a perforated box for the purpose of preventing oscillation: as it is always submerged, and the pressure upon it is equal to the weight of a column of water, having its base at the bag, and its summit at the mean level of the surface waves.

This instrument has been constructed by the United States Coast Survey, and is now in operation at the tidal station in the Boston Navy Yard.

4. American Weather Notes; by PLINY EARLE CHASE. (Read before the American Philosophical Society, March 3, 1871.-The signal service observations of our War Department have already shown the value both of Buys Ballot's law and of Capt. Toynbee's modification in predicting changes of wind, especially if due regard is paid to the barometric variations of the two previous days. They have also suggested the following general deductions, some of which may perhaps prove to be true only of the winter, while others seem to be explicable by natural circumstances of position and physical configuration, which must be operative at all seasons.

(1) Winds varying like the land and sea breezes, are often traceable, especially in the lull which follows the passage of storms, to differences of temperature in the neighborhood of the great lakes, and of mountain peaks and ridges.

(2.) The wind, especially in the Southern States, often blows directly in the line of the greatest barometric gradient. But even in such cases, after a few hours continuance, it tends toward the azimuth indicated by Buys Ballot's law.

(3.) The isobaric lines are, therefore, often of less relative importance than the gradients in forming forecasts.

(4.) Long ridges of high barometer, as observed by Espy and others, with adjacent troughs of low barometer, often traverse the continent, sometimes with slight deflection, sometimes having a semi-circular, circular, or elliptical curvature, with a diameter of three thousand miles or more. Such ridges usually have a steeper declivity and stronger winds on their northerly and easterly than on their southerly and westerly sides.

(5.) Currents with an anti-cyclonic tendency, controlled by areas of high barometer, are notably common. Keversals of wind, as from N.E. to S.W., are, therefore, frequent after the passage of

an anti-cyclonic ridge or center, as well as after the passage of a cyclone.

(6.) Our recent storms have been anti-cyclonic, and there seems some reason for supposing that anti-cyclones are the usual "weather-breeders," even of such of our land storms as become more or less cyclonic after they are fully developed.

(7.) The precipitation of vapor of course gives rise to local cyclones, which, however, may be easily and speedily overborne by the grand anti-cyclonic whirls of a half million miles or more in

area.

(8.) These and other peculiarities, point to a probable origin of storms in the blending of polar and equatorial currents, near the latitudes at which the general tendency of the winds changes its direction.

(9.) Mr. Scott has observed that when polar (E.) currents are blowing at the North, and equatorial (W.) currents at the South, a serious barometrical disturbance, frequently resulting in a gale, generally soon follows; but when the polar current is at the South and the Equatorial at the North there appears to be no law of sequence. The latter condition, with us, seems often indicative of approaching fair weather, especially if northerly or easterly are separated from southerly or westerly winds by a ridge of high barometer.

(10.) If the progress of a northerly or easterly current toward the equator is impeded by an intervening southerly or westerly current, the disturbance not only speedily follows, as indicated by Mr. Scott, but it is also, commonly, like most showers, S.E. storms, and other marked cyclonic commotions, of briefer duration than those which are primarily anti-cyclonic.

5. European and American Rain-fulls; by PLINY EARLE CHASE. (Read before the American Philosophical Society, March 3, 1871.) There is still a lingering skepticism on the part of some meteorologists, regarding the moon's influence on the weather, a skepticism which is perhaps owing to the apparent want of agreement between observations at different places. There is, however, no good reason for expecting such accurate correspondence as is sometimes deemed essential. Dr. Emerson (Proc. A. P. S., xi, 518) has communicated to the Society his early observation upon the reversal of the European Barometric prognostics on this side of the Atlantic. Mr. Blodget (Climatology, pp. 221-237) has pointed out various climatologic contrasts, and Mr. Scott, the Director of the British Meteorological Office, has noticed an opposition between the solar (or temperature) rain-falls in Western Europe and Eastern America, analogous to that which I have indicated in the lunar rain-falls. The confirmation thus afforded to the results of my previous investigations, strengthens the presumption that, in our Atlantic States, signs of fair weather may be most confidently trusted during the ten days preceding, signs of rain during the eight days following, full moon.

In order to make a comparison between stations of similar latitude, I obtained from the "Observatorio do Infante D. Luiz,” a

record of the quarterly rains at Lisbon for sixteen years, which I have embodied, together with the observations at Pennsylvania Hospital for the same period, in the following tables. The measurements are given in millimeters.

I.-Quarterly Rain-fall at Lisbon.

II.-Quarterly Rain-fall at Philadelphia.

Years. Winter. Spring. Summer. Autumn. Total Years. Winter. Spring. Summer. Autumn. Total. 1855 280-3 272-7 15.4

930 9 1855 193.0 912-9 1856 284.5 812 3 1857 1844 912 1 1858 2649 708-3 1859 376-7 560-21860 240-3 981 8 1861 269-8 830-81862 292:6 5447 1863 280-7 834:9 1864 174-8 1042-4 1865 370-1 676-9 1866 390-4 599 1 1867 230-1 557-21868 225 3 1869 323-2 158.5 3.1 66.0 550-9:1869 318.5 1870 305-7 1116 219 160-3 599.5 1870 297.7 Mean 275.2 197.9 27.9 252.5 753-4 Mean 274 6

362-5

90.3

324-4

567 6

306-9

1873

3114

176.9

1016

363.5

169 9 435 4
211·8 241.3
3599 482-6
272-8 274-1
376-9 3764
229-6 3117
362.5 2433
2545 263.1
442-0 2974
448-3 204 2

257-8 1056:1 1875 925.1

487-2

82.3

172.1

2794

195-8 1202-2

380-3
370-9 1203-8

370-6 742-5 228-1 1571-3 4013 268-0 404-6 1299-2

296-2 247-7
404 9 303-8

337-8 1200-2

326-5 323-6 287 2 1211.9

It appears, therefore, that the heaviest rain-falls at Lisbon and the lightest at Philadelphia, are usually in the Autumn and Winter semester; the heaviest at Philadelphia and the lightest at Lisbon, in the Spring and Summer. In ten years out of the sixteen, when the rain-fall of the entire year was above the average at one station, it was below the average at the other.

6. Discovery of the Animal of the Spongiada confirmed; By H. J. CARTER, F.R.S. &c. (Ann. Mag. N. H. IV, vii, 445). Just a line to tell you what you will be glad to learn, viz. that I have confirmed all that Prof. James-Clark, of Boston, has stated about the sponge-cell, and much more too.

It is, after all, only what was published and illustrated in the 'Annals' in 1857. Indeed I am astonished now at the accuracy and detail of that paper ("Ultimate Structure of Spongilla," &c.), now all confirmed by an examination of a marine calcareous sponge.

I have not only fed the sponge with indigo, and examined all at the moment, but the sponge so fed was put into spirit directly afterward, and now shows all the cells (monociliated) with the cilium attached and the indigo still in the cells.

This, I think, will break down Häckel's hypothesis, which is as imaginative and incorrect as it is beautiful.

His "Magosphæra," too, is figured in the Annals' (1856), and described in extenso as the amoeboid cell which inhabits the mucus of the cells or internodes of the Bombay great Nitella.

But there are no people in England, if on the Continent, who seem to be able to show this, if even they be cognizant of it.

Ex oriente lux used to be the old phrase; the light is now being reflected back from America. It is from there that we must expect novelties now.

"The Cottage," Budleigh-Salterton, May 22, 1871.

7. A new attachment for the Lantern.-It is often desirable to throw upon a screen the images of objects which must be preserved in a horizontal position; such for example as liquids, or solids immersed in liquids. Various devices have been tried for securing this end: all of them more or less imperfect. Recently, however, President Morton, of the Stevens Technological Institute at Hoboken, has devised a form of apparatus for this purpose which is quite simple and ingenious, and which answers its purpose admirably. This "vertical lantern" as he calls it, is shown in the accompanying figure. It is to be placed in front of the ordinary lantern-box, the condenser being composed of three lenses; the first two of these being of such a curve as to give, with the light about two inches from the nearer one, a practically parallel beam. This beam enters the apparatus at A, is received upon a mirror inclined 45°, which reflects it vertically through the third lens placed horizontally at C. This lens concentrates the beam upon the object glass at E, after passing which, it is reflected upon the screen by the silvered mirror FG. Though the lenses are all of them uncorrected, and the mirrors silvered on the back in the ordinary way with pure silver, yet there is no want of definition in the images produced, and the color is too slight to be appreciable by an audience. We witnessed the performance of the instrument a short time ago with great satisfaction. A glass plate, evenly covered with iron-filings, being placed above the lens C, a small magnet was laid beneath it, A and the plate gently tapped with a pencil. The filings gradually arranged themselves in the wellknown curves, producing finally a magnetic spectrum of great beauty. A shallow tank of water being then placed in the same

position, the images of waves, ingeniously produced by puffs of air, were thrown upon the screen, and the various phenomena of interference and reflexion beautifully illustrated. Tomlinson's cohesion figures, produced by allowing drops of various essential oils to fall upon water, were also superbly demonstrated. By using thin glass plates covered with sand, Chladni's sound figures may in this way be developed upon the screen in a striking manner. The apparatus was manufactured by Messrs. Hawkins & Wale of Hoboken. It is exceedingly creditable to them in the excellence of its construction and finish.

G. F. B.