upon the height of the mercurial column or its daily tides, which take place about 3 a.m. and p.m. for minima, and 94 a.m. and p.m. for maxima. The range is about 0.110 in., but occasionally it amounts to 0.180 in.

Temperature. The lowest temperature of the year occurs in December, though sometimes it may be in November, January or February, and the highest usually takes place in April, but it may be noticed in the preceding or subsequent month. In this record the minimum, 57°, took place in December, and the maximum, 97°-5, in May. The monthly means make the extremes in December and April. The Tension of Vapour follows a similar rule, viz. the lowest in December and highest in May, but the tables of Humidity and Rainfall are different; these agree in making December the minimum and September the maximum of the year. The years 1859 and 1864 were remarkable for little rain, years of drought, in 1865 rice was imported, whilst 1860 and 1868 were the years of greatest rainfall.

Hail occurred only once, one afternoon, during my residence of fifteen years.

Winds.-In September the SW monsoon becomes weak; early in October N breezes set in, varying from W to E by the northern segment, and during this month or November the NE monsoon is quite established. Throughout December it continues strong, but in January it has lost half of its last month's vigour, and in February retains only a fifth of its original force; the deficiency being in part made up by an increase of wind varying from SSE to SW. By the end of the month or early in March the N winds have ceased and strong breezes from S and SSW prevail, locally termed the Kite and Junk winds. It is in April that the greatest heat takes place, and for two or three nights in succession, if no breeze stirs the air, the plight of foreigners, ay even of natives, is not to be envied. During the months of May, June, July and August, the SW winds are strong and constant, sometimes boisterous, the direction being chiefly S and SSW till June, and thence SW to September, when light variable winds are the rule, and foretell a breaking up of the SW monsoon.

PROCEEDINGS AT THE MEETINGS OF THE SOCIETY.

NOVEMBER 20th, 1878.

Ordinary Meeting.

CHARLES GREAVES, M.Inst.C.E., F.G.S., President, in the Chair.

Rev. THOMAS LEO ALMOND, O.S.B., St. Gregory's College, Downside, Bath; Rev. THOMAS CALVERT BEASLEY, M.A., Dallington, Northamptonshire;

FRANCIS THOMAS BIRCHAM, Burhill, Hersham, Walton-on-Thames;

HENRY F. BLANFORD, F.G.S., Meteorological Office, Calcutta ;

GEORGE CHATTERTON, B.A., 46 Queen Anne's Gate, S.W.;
EDWARD EASTON, M.Inst.C.E., F.G.S., 9 Delahay Street, S.W.;
WILSON LLOYD Fox, Falmouth;

GEORGE FOSBERY LYSTER, M.Inst.C.E., Dock Yard, Liverpool;

Lieut.-Col. WILLIAM STUART, D.L., J.P., Tempsford Hall, Sandy;
ROBERT TENNENT, F.R.S.E., 21 Lynedoch Place, Edinburgh; and
HENRY YOOL, Oakfield, Weybridge,

were balloted for and duly elected Fellows of the Society.

Mr. E G. ALDRIDGE and Mr. R. J. LECKY were appointed Auditors of the Treasurer's Accounts.

The following Papers were read:

Report on the Phenological Observations for 1878." By the Rev. T. A. PRESTON, M.A., F.M.S. (p. 42.)

"Up-Bank Thaws." By the Rev. FENWICK W. STOW, M.A., F.M.S. (p. 64.)

"Results of Observations made in different Screens on board Ship, by Captain William Watson, F.M.S." Compiled in the Meteorological Office, and communicated by Captain HENRY TOYNBEE, F.R.A.S. (p. 72.)

The Meeting was then adjourned.

DECEMBER 18th, 1878.

Ordinary Meeting.

CHARLES GREAVES, M.Inst.C.E., F.G.S., President, in the Chair.

PATRICK DOYLE, F.S.S., M.R.A.S., Perak, Straits Settlements;
JOHN MCDONALD GRAY, 2 Salem Street, South Sunderland;
Right Hon. Lord HAMPTON, G.C.B., F.R.S., 9 Eaton Square, S.W.;
MOSES JACKSON, The Vale, Ramsgate;

ALBERT PROCTOR, Turnagain Lane, Farringdon Street, E.C.;
GEORGE SIMPSON, Wray Park, Reigate, Surrey; and
EDMUND CHARLES TISDALL, Horton, Epsom,

were balloted for and duly elected Fellows of the Society.

The SECRETARY read the following letter:

"Royal Observatory, Greenwich, S.E., “August 12, 1878.

"DEAR SIR,

"A very elaborate work of the Meteorology of Colába (Bombay), and of the Bombay Presidency in general, has been prepared by Mr. Chambers (Superintendent of the Bombay Observatory), and is now printed at the expense of the Government. It is probably one of the most complete Meteorological Monographs that has ever been composed. Viewing the high character of this work, it has occurred to me that the Meteorological Society might probably be willing to make it known to the Meteorological public, through the medium of the Society's transactions; and, at my request, Mr. Ellis, of this Observatory, has drawn up an abstract of the work, which I think will be found in every way adapted to that object. I take the liberty of transmitting the abstract herewith, and I request you to lay it before the Council of the Meteorological Society, with my request that the Council will consider whether the abstract may not properly be published in their transactions.

"William Marriott, Esq.,

"I am, dear Sir,

"Yours very faithfully,

Assistant Secretary of the Meteorological Society."

"G. B. AIRY.

Abstract of "The Meteorology of the Bombay Presidency. By CHARLES CHAMBERS, F.R.S., Superintendent of the Colába Observatory." By WILLIAM ELLIS, F.R.A.S.

IN a considerable quarto volume printed by order of her Majesty's Secretary of State for India, Mr. Chambers has given the results of a systematic discussion of the meteorological observations made at the Colába (Bombay) Observatory, under the direction of the Superintendent of the Observatory; and of those on a lesser scale, made at four other stations (Belgaum, Poona, Deesa and Kurrachee) in the Bombay Presidency, under the direction of officers of the Royal Engineers. Observations corresponding to those made at the four stations mentioned, were taken also at Bombay, in addition to the more extended series, the discussion of which forms a principal part of the present volume. In a subsequent division of the work Mr. Chambers has further collected the results of such observations of temperature, wind, and rainfall as have been made at other places in the Presidency, using the whole to give a general account of these points of the meteorology of the Presidency.

In an introductory chapter Mr. Chambers defines the direction which he considers should mainly be given to meteorological inquiry at the present time. He remarks that "The faculty which enables the enthusiastic inquirer to imagine such physical conditions and actions as would, consistently with established facts and laws, produce effects corresponding in kind to the observed facts, and to calculate or estimate their adequacy to produce effects of the magnitude of those observed, finds wide scope for exercise in the consideration of observational phenomena; but it is not in speculations of this nature that experience of the past would counsel the student in meteorology to spend his energies mainly. It is rather to the accumulation of well-ascertained phenomenal laws, as educed from observations at numerous stations widely distributed over the world, and taken under all varieties of conditions as to times and seasons, that we must look, as means to safe inductions, leading ultimately to physical causes that shall embrace all the observed phenomena.'

The climatic conditions of the earth's surface vary with change of place and with change of time. The student has two problems: first, at any given time to determine the relations which subsist between the absolute values of the meteorological elements as we change our position; and secondly, at any given place, to determine the relations which subsist between the absolute values of meteorological elements as we change the time. The first of these it has hitherto been impracticable to attack directly. But the changes which follow at any place, upon change of time simply, are known to be in the main periodical in character, the principal periods being a day and a year. Mr. Chambers treats of the separation of the observed values of any element into its constant or normal, and its periodical parts, and adds (page 4) :-"Two great advantages are gained by the artificial separation, in the manner indicated, of a phenomenon into normal and periodical components: first, that the components, when viewed separately, are of simpler character, and therefore are more readily comprehended than the original complex phenomenon; and, secondly, that, as the physical cause of a variable component must itself be subject to a variation having the same period, it limits the search for efficient causes to such as are subject to that period, and thus directs inquiry into fruitful channels. On the other hand, the normal component must be regarded as a measure of the average effectiveness of all the causes that are in operation."

The work is divided into four parts. In Part I. is given a sketch of the history and character of the Colába Observatory and an account of the records, of the Observatory proper, available for use, followed by a considerable discussion of the whole. Part II. treats of the observations made at the small observatories maintained at the military stations before-mentioned (including the observations made on the same plan at Bombay). Part III. gives the principal results of observations taken at the civil and military hospitals, and of rainfall returns from Revenue officers. Finally in Part IV. the whole body of results is combined so as to exhibit some principal points in the general character of the climate of the Presidency, and its variations under change of physical conditions, and with change of season.

Before proceeding with a description of the instruments at Colába, Mr. Chambers remarks (page 8) :

“The treatment that we propose to apply to the observations of each meteorological element in succession is, first, to find the most probable absolute value of the element; secondly, to examine whether it is subject to any secular change which the observations are precise enough to exhibit; thirdly, to determine its periodical variations; fourthly, to determine its variability, and its range of variation, and the limits thereof, at different seasons; and, lastly, to exhibit all the results arrived at, as concisely as possible, by means of suitable diagrams. The elements that will be thus treated are, barometric pressure, temperature of the air, pressure of vapour, temperature of the ground, rainfall, and direction and velocity of the wind; and observations of other phenomena, of less definiteness of character than these, or such as require less attention, will be treated in a less elaborate manner."

He further considers (page 8) that " as a means of concise representation of phenomena of observational science, graphical constructions are greatly superior to verbal descriptions; for by means of them, the eye can take in, at one view, a body of facts which it would require a considerable effort of memory to retain and consider by a single mental operation, after verbal communication of them ; we regard it therefore as conducing to economy of mental effort to make a free use of graphical constructions."

...

The same barometer at Colába was used throughout, Newman No. 58; the internal diameter of its tube being 0.530 in. There is a suspicion (page 9) that the absolute pressures observed with it may not be quite the true pressures, but that "they must be regarded as subject to correction when an authentic standard becomes available for comparison with Newman No. 58."

Table I. gives the mean monthly values of barometer for Colába corrected for temperature, but not reduced to sea level, for each month, for the years 1847 to 1872; and Table II. the mean value for each day of the year, as deduced from the observations for the twenty-four years ending 1870. In a table of the latter kind it becomes necessary to exclude by some means the influence of variations of accidental character. Mr. Chambers remarks that the usual method of effecting this is to apply what is commonly know as Bessel's process for finding an expression for a periodical phenomenon, which assumes that the law of variation may be expressed by the superposition of a series of simple variations whose periods are once, a half, a third, a fourth, &c. of that of the observed phenomenon. But he finds, as will frequently be the case, that although diurnal variations may generally be closely represented in this way, annual variations cannot be so satisfactorily represented. He shows graphically the barometer curve for the year, as observed, and also that given by dividing the year into seventy-three equal groups, and applying Bessel's formula carried to six terms, but the latter does not sufficiently completely represent the observed curve. adds a curve, found by an arbitrary process, which he considers is to be preferred. His process is to take means of successive pairs of the observed values, forming (according to the method employed by the Astronomer Royal in dealing with the Earth Current records) smoothed means. He does this six times. Finally he takes the mean of the first fifteen (six times smoothed) values in January, and considers this to be the normal value for January 8: the mean of the fifteen values January 2-16 he considers to be the normal value for January 9, and so on. In other cases of annual variation, afterwards treated, Mr. Chambers constantly uses this same method, in preference to Bessel's formula, although he adopts the latter for diurnal and other variations.

He

In Table VI. is given the mean diurnal variation of the barometer in each month of the year. In each month Mr. Chambers has applied Bessel's formula carried to four terms. It is interesting to note how the several coefficients and angles vary in the different months, arriving severally at their epochs of maxima and minima at different parts of the year. Mr. Chambers shows the diurnal variations also by graphical construction: indeed diagrams have been throughout provided in a lavish manner with the view of conveying better to the eye

An expression of the form

x = m + a. sin (9 + A) + b. sin (20 + B) + &c. in which m, a, A. b, B, &c., are constants.

the character of the changes of the various elements. Tables follow giving the extreme single readings, and the extreme daily and monthly means in each year from 1847 to 1872, and also the extreme single readings and daily means in each of the twelve months of the year. These extremes are also all graphically represented. He deduces the comparative frequency and probability of occurrence of pressures within certain limits in each half month of the year, and discusses the relative magnitude of "abnormals," or deviations of mean daily pressure from the normal pressure, in each half month of the year.

Before giving any results in regard to temperature, Mr. Chambers discusses the question of thermometer exposure, and also, at some length, the influence of radiation. In the last adopted form of exposure the thermometers are mounted on light wooden rods, inside an open cage, with venetian sides and depressed venetian bottom; the cage being supported by four corner posts, which enter the ground, leaving its open bottom at a height of 3 feet, and the bulbs of the thermometers 4 feet from the soil; the cage is 3 feet square, and 5 feet high, with closed roof; and it is placed under the middle of an open shed.

Tables follow in regard to temperature analogous to those described for barometric pressure: the whole treatment is generally similar to that in the barometric section.

The pressure of vapour is found from the readings of the dry and wet bulb thermometers by Apjohn's formula, and tables referring to pressure of vapour are given much in the same way as for the other elements. These results are discussed at some length, and also in connection with prevalent winds.

There follows some results in regard to the amount of cloudy sky, after which the thermometers for indicating earth temperatures are described. Of these there are several, the bulbs of the two that are deepest being respectively 5 feet and 12 feet below the surface. The 12-foot thermometer after a few years' observations was accidentally broken in the hurricane of November 1-2, 1854, and has not since been replaced. The mean annual variations of the 9-inch, 20-inch, 5-foot and 12-foot thermometers have been treated by the process used by Professor J. D. Everett in dealing with similar results obtained from observations made at Greenwich Observatory. Mr. Chambers finds for the value of the thermal co-efficient for Bombay, referred to the English foot, 01149, or 0-1225, as referred to the French foot. Unavoidably the series of observations of the different thermometers does not extend over quite the same years, but the result is probably not essentially altered by this circumstance. The corresponding numbers found at other places, as referred to the French foot, are:

Mr. Chambers comes now to the important question of rainfall. He gives the rainfall in each month for 32 years, and points out that the results somewhat confirm the supposed connection between rainfall and sun-spots pointed out by Mr. Meldrum. He gives also the average rainfall for each day, the greatest and least amounts collected in one hour, one day, and one month, in different years, the proportion at different hours of the day, and the comparative frequency of falls of definite magnitude in each half month of the year, with some remarks on the variation in the amount of rainfall with altitude. This appears to be least with heavy rains, that is, at such times the falls are more nearly equal.

The anemometer was a Robinson anemometer with improvements by Mr. Beckley. The centres of each pair of opposite hemispherical cups are 4 feet apart, and the diameter of the cups is 9 inches. Movement and direction of the wind are registered on the same sheet. Tabulations of movement and direction have been made for two-hourly periods during seven years. The movements have been resolved into northerly and easterly components, mean values of which are given for every month of observation: mean values are also

• The same thing has been remarked at the Royal Observatory at Greenwich. The amount collected at an elevation more nearly equals that collected on the ground when the rain is heavy, although there is another circumstance to be remembered, which is that at such times the air is usually more nearly calm.