I never visit the Louvre without stopping at his mosque of Colouglis, to view its lofty chalk-white domes, and its attenuated towers; and then I mingle among the Turks assembled below, observe the traffic they carry on, and shelter myself from the burning sun with my wide-extending umbrella; or else I walk with the painter through his wide street of Babazoun, and look askance towards the latticed windows to see whether some concealed female form does not hold out a billet-doux. The artist has painted his objects with such a glowing heat, that the eye seems to seek relief from the burning flags amidst the shades of the edifices. It is easily observed how the people who walk about "drag their slow length along,"-so languid and weary do they seem, with such indifference do they apply to the concerns of life. All the apartments and courts around invite to rest or sleep, or to enjoyments and gratifications. It is the East and Eastern life we behold, where every thing withers and burns up as in a volcano. It is difficult to describe all this even in painting. We must have been in this consuming climate, and, as it were, tattooed on the tablets of our memory its glowing colouring, as Fatio and Langlois have done. In The latter artist has given to the public another battle-scene with the Arabians-the contest of Sediferruch, fought on the 13th of June, 1830. In this picture the Turks, occupying the foreground, "imitate the action of the tiger," in their brave resistance. Their artillery has a very singular appearance, being served by artillerymen in Turkish great coats, resembling bed-gowns. the back-ground is seen the Mediterranean Sea, blue as the sky,→ the French fleet is in line of battle, sending on shore sharpshooters, whilst two frigates discharge their broadsides against a battery. The valiant soldiers, in their night-gowns, fall one by one. The troops which have been disembarked advance under a cloud of smoke, having at their head General Achard, a bas le Dey! The contest is lively and stirring. This is the utmost that can be said of such kind of pictures. The colouring is not near so true as in the pictures of Fatio and Decamps. The merit of Langlois in composition is however very considerable-his drawings possess energy, boldness, and life-admirable qualifications for battlepieces. AUTHORS.-J. A. Paradis di Moncrief, a French author, who died in 1770, wrote, when young, a history of the cats, which drew upon him many sarcasms and epigrams. Roi, the poet, having made a severe one, Moncrief laid wait for him, as he came out of the Palais Royal, and caned him heartily; but Roi, who was accustomed to such things, being no less supple than malignant, turned his head to Moncrief. and holding out his back to the stick, said quietly, "play gentle pussy, gently play." THE HEIGHT OF THE WORCESTERSHIRE BEACON, ABOVE THE LIBRARY, GREAT MALVERN, Deduced by the formulæ of Maskelyne, Hutton, and Daniell, from two BY W. ADDISON, F. L. S., SURGEON TO HER ROYAL HIGHNESS THE DUCHESS OF KENT, MALVERN. THE barometric measurement of hills or mountains is an operation of great nicety, and the results can only be considered as very rough approximations, unless all the corrections for the moisture and temperature of the air are duly attended to. Ever since the celebrated and important experiment of Torricelli, the attention of some of the greatest philosophers has been drawn in succession to this interesting problem; and the difficulty of estimating the quantity and effects of aqueous vapour has hitherto been one of the chief obstacles to the attainment of accuracy. Daniell's hygrometer appears better calculated than any other instrument to remove this obstacle. This Hygrometer was used in the measurement of the height of the Worcestershire Beacon, which I am now about to detail. Dr. Maskelyne's formula for determining the height of mountains by the barometer is as follows: 1. Take the difference of the tabular logarithms of the observed barometrical heights, at the two stations, considering the first four figures (exclusive of the index) as whole numbers. 2. Observe the difference of Fahrenheit's thermometer at the two stations; multiply this difference by 0.454, and add or subtract this product according as the thermometer was highest at the upper or lower station-which will give an approximate height. 3. Take the mean between the two altitudes of the thermometer and find the difference between this mean and $2o. Multiply the approximate height by this difference, and the product by the decimal fraction 0.00244. This last correction being added to or subtracted from the approximate height, according as the mean of the two altitudes of Fahrenheit's thermometer was greater or less than 32°, will give the true height of the upper station in English fathoms. Dr. Hutton's rules are as follows: 1. Let the heights of the barometer at the top and bottom of any elevation be observed as near the same time as may be, as also the temperatures of the attached thermometers, and the temperature of the air in the shade at both stations, by means of detached thermometers. 2. Reduce these altitudes of the barometer to the same temperature, by augmenting the height of the mercury in the colder temperature, or diminishing that in the warmer by its every degree of difference between the two. 3. Take the difference of the common logarithms of the two heights of the barometer (so corrected) considering the first four figures as whole numbers-which will give an approximate height. 480 4. Take the mean of the two detached thermometers; and for every degree which this differs from 31° take so many times the 1 part of the approximate height; and add them, if the mean temperature be above 31°; but subtract them if it be below 31° and the sum, or difference, will be the true altitude in English fathoms. These formulæ have been somewhat modified, and perhaps improved by subsequent philosophers. The following proceeding is recommended by Mr. Daniell in his Meteorological Essays, being, in fact, mainly Dr. Hutton's process, with additional corrections for the elasticity and density of the air, consequent upon the presence of more or less vapour, at either of the observed stations. 1. Observe the heights of the barometer at the top and bottom of any elevation, and the heights of the attached thermometers. Observe also the temperature of the air in the shade at the two stations, by a detached thermometer: the dew point must also be accurately taken at the upper and lower situation-these observations being made as nearly as possible at the same time. 2. Correct the heights of the barometer observed at the top and bottom of the station, for the expansion of mercury and the mean dilatation of the tube (by the table) to the temperatures observed by means of the attached thermometer, at these two stations. 3. Take the difference of the common logarithms of the two heights of the barometer (so corrected) considering the first four figures as whole numbers-which will give an approximate height in fathoms. 4. Find the mean of the two temperatures observed by the detached thermometer, in the shade, at the upper and lower station-and (referring to the table) note the expansion of air due to this mean temperature, and subtract it from 1.00000 which will give the specific gravity of the air corrected for temperature. 5. Note the temperature of the constituent vapour of the atmosphere, by finding the dew point at the upper and lower station. 6. Find the expansion of air for vapour at these two observed points (by the table), and subtract from each of them the increase of density which air undergoes for vapour (found by the table) at the same points; and the mean of this result, subtracted from the specific gravity of air corrected for temperature (4) will give the correct specific gravity of the air.-And then say— 7. As this correct specific gravity is to 1.00000 (the standard) so is the approximate height (3) to the correct height.* *The Tables referred to above, will be found in Daniell's "Meteorological NO. VI. 3 G Taking the first series of observations, and proceeding according to Maskelyne's process-we obtain 921 feet as the height of the Worcestershire Beacon.-Thus 2. Temperature at the two Stations. 64 and 53, diff. 11° 0.454 = 4.994 Approximate height in Fathoms, 144.190 Essays," Second Edition, viz. that for the Expansion of Mercury, and the mean dilatation of Glass, p. 372. Table of Expansion of Air for Temporature, p. 177. Table of Expansion of Air for Vapour, p. 177. Table of Increase of Density of Air for Vapour, p. 177. 3. Temperature at the 64 and 53 mean 58.5-32 = 26.5 two Stations. 6428.5 23 144.1903821.035 Proceeding in the same way with the second series of observations-we obtain 934.596—and a mean of these two numbers gives 927.937 feet. The height deduced by following the method of Dr. Hutton isfrom the first series of observations 910.800 feet-and from the second 927.882, the mean being 919.341 feet. The greatest reliance ought perhaps to be placed upon the results obtained by following Daniell's formula, because it embraces the important corrections necessary for the vapour always in a greater or less degree existing in the air. Following his directions, the height, by the first series of observations, is 924.01 feet; and by the second, it is 925.50 feet; a remarkably close approximation. The mean of the numbers obtained by Maskelyne's and Hutton's formulæ, is 923,639. The details of Daniell's formula are subjoined, taking the second series of observations as data. Then .93960 1.00000: 869670 925.5 the height in feet. .93002 .00864 .00958 |