purposes in France is seen by the fact that 1000 communes will by the end of the first year be in receipt of free daily forewarnings from the Paris Observatory.

Among the newest attempts to investigate the meteorol ogy of the upper strata of the atmosphere, we note the establishment by Secchi of a complete observatory on the summit of Monte Cavo, 2800 feet above the Roman Campagna.

The meteorology of the Libyan Desert forms the subject of the second volume of Rohlf's Expedition. The editor, Dr. Jordan, finds that the diurnal barometric range is unusually large. The daily range of temperature is 24°; the mean relative humidity at 2 P.M. is 17 per cent. Half an inch of rain fell in February-a matter of rare occurrence.

With the 1st of January the weather maps published by the meteorological offices in Germany and Austria have received considerable enlargement and improvements. The daily weather map published at Vienna is for Europe the best that has as yet appeared, being upon a large scale, and very clear in all its details. The Hydrographic Office at Berlin has begun the publication of monthly weather reviews for Europe. Its articles are compiled and signed by well-known meteorologists; and as it appears only a long time after the month to which it refers, its scope and objects. are evidently somewhat different from those of the reviews published by our Army Signal Office.

The Monthly Weather Review deserves a wider circulation than it appears to have in this country. It consists of ten or twelve pages of text and three maps, and gives in a very condensed review all the matter received by our Weather Bureau within fifteen days after the close of the month.

Perhaps the most interesting event that has occurred of late years to extend our means of studying the storms of the atmosphere consists in the important order issued on Christmas-day, 1876, by the Secretary of the Navy, to the effect that, wherever our vessels may be, there shall every day be made a complete meteorological observation, simultaneously with those made at Washington at 7 h. 35 m. A.M. It is hoped that the other navies of the world will unite in this simultaneous system of weather observation, and that the merchant marine will follow so far as able. These observa

tions will form an important part of the Bulletin of International Simultaneous Meteorological Observations, to which so many nations contribute, in response to the invitation of General Myer and the advice of the Vienna Meteorological Congress. The British and United States merchant marines have already voluntarily added valuable observations to this Bulletin. The navies of Portugal and France also contrib

ute.

We learn from the Japan Weekly Mail that an excellent pamphlet on meteorology has been published by Mr. Joyner, of the Meteorological Department at Tokio, in which he advocates strongly the establishment in Japan of an extended system of observations by carefully trained observers. Such observations have hitherto been made by Mr. M'Vean and Mr. Joyner for the Department of Public Surveys, and by some of the Americans stationed as professors in the other government institutions.

The International Congress of Meteorologists that was appointed to be held in Rome in September having been deferred to September, 1878, the advocates of a series of international Polar expeditions (Messrs. Wilczek and Weyprecht) have widely circulated their programme, detailing the work to be done, which, of course, largely relates to terrestrial physics. It is proposed that each station be occupied one whole year; besides the usual meteorological observations, particular stress is laid upon observations of ice, tides, auroræ, magnetic phenomena, and earth currents.

As these proposed international Polar stations are for purely scientific investigations, and as their plan so perfectly harmonizes with the Howgate plan of an Arctic colony, it is to be hoped that our own government will establish, at least, two such scientific stations-one at Point Barrow, the other to the north of "Hall's Rest."

The sixth annual report of the Superintendent of the Meteorological Service of the Canadian Dominion, presented by Carpmael in the absence of Professor Kingston, shows the continued activity of the office in gathering meteorological observations from the entire northern portion of America. Twenty new rainfall stations have been established in British Columbia; five new complete stations in the northwest territories; eleven in Ontario; two in Manitoba, etc. In

all, 120 stations report to the Central Office. Telegraphic reports are received from stations in the United States and the Dominion sufficient to allow the office to issue its own daily weather predictions and storm warnings independent of those received from the office at Washington. The work of the office for the year has been highly complimented by the Toronto Board of Marine Exchange.

Detailed tables of observations and averages, etc., accompany the report, as in former years, together with short reports from the observatories at Kingston, Quebec, Montreal, and St. John.

Early in 1877 the large volume containing the meteorological and physical observations of the Polaris Arctic Expedition was published by the National Academy of Sciences. As only a very small edition of this volume was printed, we shall give a somewhat extended résumé of its contents as soon as Dr. Bessels has published the results of his revision of the work. Among the interesting items that Dr. Bessels announced was the demonstration of the fact that in Smith Sound there meet two opposing tidal waves from the north and south, confirming the theory that Greenland is an island. The same fact is now independently deduced by Rev. Samuel Haughton from the tide observations of the British Polar Expedition, and a deserved tribute should be paid to Dr. Bessels's sagacity.

Some progress has been made in the formation of state meteorological associations in the United States. The first annual report of the Iowa weather stations shows that about ninety observers report to Professor Hinrichs, who in various. ways finds opportunity to foster an increasing intelligent interest in the subject of meteorology. The rainfall map for Iowa is published monthly, and is a most praiseworthy contribution. An enthusiastic beginning has been made by Professor Nipher, of St. Louis, who will publish monthly reports of "The Missouri Weather Service."

The first steps have been taken towards the organization. of a state system of reports in Illinois. The statistics generally published annually by the regents of the University for New York, and by the Secretary of State for Ohio, together with the data given in the annual reports of various Boards of Public Works, Chambers of Commerce, Boards of Trade,

etc., show that there is a considerable independent activity in weather observation.

INSTRUMENTS AND METHODS.

The application of the thermo-electric pile to the study of terrestrial radiation has been treated of by Frölich in Wild's Repertorium. He employed a blackened surface as his normal standard; this was heated to known temperatures, and its effect upon the pile observed. An empirical formula was thus obtained, which gave the temperature of the surface as a function of the movements of the galvanometer needle. The instrumental constants being thus known, the face of the pile is to be turned towards the sky, and the temperature then observed becomes the basis of further computations, whence the mean temperature of the atmosphere and eventually the mean temperature of exterior space may be deduced. As illustrating his results, Frölich deduces for the mean temperature of the atmosphere -17° C. on August 17 and -36° C. on October 23, 1876.

Dr. Buff, of Giessen, describes a method by which he attempts to make the thermo-electric pile an important meteorological instrument. He claims that it enables us to measure the greater part of that portion of the sun's rays which has not yet been converted into sensible heat. Dr. Buff's method of operating consists in exposing both ends of the pile to the temperature of the air when the needle assumes its zero position. The upper end is then exposed to any portion of the sky, when, of course, the needle indicates heat or cold, according to the position of the sun and condition of the sky. If, now, a plate of glass is held as a screen to this exposed end, it cuts off all rays of low refrangibility, and the needle returns partially, but never during the daytime entirely, to its zero. With a perfectly clear sky, and without the glass screen, the radiation of the exposed end caused, for instance, an indication of −50°, but protected by the glass screen an indication of +10°. On another day the blue heavens gave -30°, the glass screen +20°, and the clouds +50°. The ends of the pile are covered with lamp-black, whose radiation is nearly the same as that of the green leaves, and the instrument, therefore, gives a just idea of the range of temperatures to which leaves are subject. It is a

most important instrument to those engaged in investiga. tions bearing on the growth and distribution of plants, as well as to the physical meteorologist.

The importance of knowing the sum total of the temperatures at any place for various meteorological and phænolog ical studies, lends value to the suggestion of Steinecke that clocks uncorrected or anti-corrected for temperature be introduced as a part of the meteorological apparatus. Such clocks or chronometers, called thermo-chronometers, have long been used in longitude determinations and for rating chronometers, and will abundantly answer the required purpose. But for meteorological purposes, self-recording thermometers, in connection with Ausfeld's planimeter, offer every facility for accomplishing the same end cheaper and better. The idea of temperature clocks is also worked up by Mr. F. Stanley in the Quarterly Journal of the London Meteorological Society.

Of the numerous precautions to be taken in using the wetbulb thermometer, we find some account in Marriott's report detailing the results of observations on ten wet and three dry thermometers all enclosed in the same cage. It is necessary that all should be covered with the same kind of mus lin, which should be very thin, and be connected with the water reservoir by six or eight threads of yarn tied to the upper end of the muslin. For the minute yet important details we must refer to the volume itself.

The formula for correction of the instrumental errors of the aneroid are given by Von Wullerstorff Urbain, who exemplifies them by an example drawn from the record of the ship Tegetthoff.

In the course of his remarkably accurate investigation into the truth of the Boyle or Mariotte law, Mendelleff invented an improvement upon the barometer-undoubtedly one of the most important that has ever been suggested. It consists simply in terminating the upper end of the barometer tube by a capillary tube bent downward. By means of this it is possible to cut off and expel the last trace of any foreign gas that may remain in the vacuum chamber. He thus obtains a perfect instrument without boiling the mercury in the tube. His determination of the correction for capillarity and his method of measuring the barometric press