William Napier Shaw

“ Thus a belt 46° 54′ in angular width will be suitable for a sunshine recorder for any part of the world. Whatever place be chosen for the observation the same belt will do if it is set up perpendicular to the earth's polar axis. But there can be no record if the sun is below the horizon; hence any part of the belt projecting above the horizon is not only useless for recording but is liable to shadow a part of the belt where there might be a record. ”

“ Thus the artificial formation of dew and consequent determination of the dew-point is a recognized method of measuring the pressure, and thence the amount of water vapour in the atmosphere. The dew-point method is indeed in some ways a fundamental method of hygrometry.
The dew-point is a matter of really vital consequence in the question of the oppressiveness of the atmosphere or its reverse. So long as the dew-point is low, high temperature does not matter, but when the dew-point begins to approach the normal temperature of the human body the atmosphere becomes insupportable. ”

“ It seems possible to draw a distinction between mist and haze that would be fairly well supported by usage. Mist may be defined as a cloud of water particles at the surface of land or sea, and would only occur when the air is nearly or actually saturated, that is, when there is little or no difference between the readings of the dry and wet bulbs; the word haze, on the other hand, may be reserved for the obscuration of the surface layers of the atmosphere when the air is dry. ”

“ Examples of all degrees between the comparatively unimportant rain line and the most violent tornado-like squall could be put side by side with cases in which the typical pressure, temperature and weather changes are accompanied by a sudden lull in the wind, as in the example quoted in the Life History of Surface Air Currents (M. O. publication, No. 174, 1906) . An example of a line squall in its most violent and destructive form is shown in the records for the 1st of June 1908. ”

“ We may thus define a fog as a surface cloud sufficiently thick to cause hindrance to traffic. It will be a thick mist if the cloud consists of water particles, a thick haze if it consists of smoke or dust particles which would be persistent even in a dry atmosphere. ”

“ It can hardly be maintained that no dew could form unless there were a supply of water by evaporation from warm ground, but, when such a supply is forthcoming, it is evident that in place of the limited process of condensation which deprives the air of its moisture and is therefore soon terminable, we have the process of distillation which goes on as long as conditions are maintained. ”

“ The air which remains after the passage of a line squall is, how- ever, distinctly colder, of an entirely different kind from that which it replaces and, in those cases which have been investigated, can be traced back to a different point of the compass. ”

“ A priori we might suppose that the formation of fog would arrest cooling by radiation, and that fog would thus act as a protection of plants against frost. The condensation of water evaporated from wet ground, which affords the material for making fog, does apparently act as a protection, and heavy watering is sometimes used to protect plants from frost, but the same cannot be said of fog itself—cooling appears to go on in spite of the formation of fog. ”

“ At the British Association meeting at Cambridge in 1904 he presided over the subsection for astronomy and cosmical physics, and there advocated the organisation of meteorological work upon an imperial basis and an imperial provision 'for organised observations from areas too wide to be within the control of any single government.' He died suddenly of apoplexy on 18 March 1908 at Bon Porto, the estate which he had acquired on account of his wife's health at Var in the south of France. He was buried within his own estate. An accomplished musician, he played well on both the organ and the piano. ”

“ It is not radiation alone that is necessary to produce dew, nor even radiation from a body which does not conduct heat. The body must be surrounded by an atmosphere so fully supplied with moisture that the dew-point can be passed by the cooling due to radiation. ”

“ Gale force is defined for the purposes of the meteorological office as that of a wind which has an average velocity during an hour of 38 m. per hour. According to Simpson's results at Scilly or Holyhead, where the exposure is good, a wind that just got within the reckoning of gales would reach 44 m. per hour in the ordinary gusts, with occasional records of 51 m. per hour. Squalls with velocities reaching 55 m. per hour are not uncommon, and the range of wind velocity which constitutes a squall may be anything between 40 m. ”

“ The persistence of these fog wreaths is always remarkable when one considers that the particles of a fog cloud, however small they may be, must be continually sinking through the air which holds them, and that unless some upward motion of the air keeps at least a balance against this downward fall, the particles of the cloud must reach the earth or water and to that extent the cloud must disappear. ”

“ In 1887 Buchan was appointed by the Royal Society of London a member of the meteorological council, which from 1877 to 1905 administered the parliamentary grant for meteorology and directed the operations of the meteorological office in London.
From 1878 to 1906 he was librarian and curator of the museum of the Royal Society of Edinburgh, and thus came into constant relations with the chief Scottish men of science. He was secretary of the Royal Society Club, a social coterie of the fellows. ”

“ The numerous tables in the text co-ordinate a vast mass of data, and the fifty-two coloured maps show the mean temperature, isobaric lines, and prevailing winds over the globe, for each month of the year and for the year, while two plates of curves indicate the deviations at different hours of the day from the mean daily temperature, mean daily atmospheric pressure, wind velocity, and the like. ”

“ SQUALL, the name given to any sudden increase of wind to gale force. Generally speaking a squall is understood to be of short duration, but the word " gust " would be used to indicate an increase of wind force of more transient character than a squall. Gusts may succeed one another several times within the compass of a minute. A squall may comprise a succession of gusts, with intervening partial lulls, and would last with varying intensity for some minutes at least. ”

“ Coast fog, which is probably of the same nature as land fog, is most frequent in the winter months, whereas sea fog and ocean fog is most extensive and frequent in the spring and summer. By June the fog area has extended from the Great Banks over the ocean to the British Isles, in July it is most intense, and by August it has notably diminished, while in November, which is proverbially a foggy month on land, there is hardly any fog shown over the ocean. ”

“ In sheltered valleys it is easy to suppose that the constant downward drainage of fresh and colder fog-laden material at the surface supplies to the layers displaced from the bottom the necessary upward motion, and the result of the gradual falling of drops is only that the surface cloud gets thicker; but there are occasions when the extent and persistence of land fog seems too great to be accounted for by persistent radiation cooling. ”

“ As examples of the cutting of the belt for different latitudes we may put side by side the recorder as used in temperate latitudes (fig. 1) and the special form designed in the Meteorological Office, London, for use on the National Antarctic Expedition, 1901-1904 (fig. 2) . A belt cut for a particular latitude is serviceable for some 10° on either side of that latitude if the cards are not trimmed too must always be closely to the cutting of the belt. ”

“ One cannot therefore observe under ordinary circumstances both the temperature difference and the fog. Doubtless one requires not only the initial temperature difference but also the slow drift of air which favours cooling of the lower layers without too much mixing and consequently a layer of fog close to the surface. Such a fog, the characteristic sea fog, may be called a cold surface fog. From the conditions of its formation it is likely to be less dense at the mast-head than it is on deck. ”

“ Moreover, the smallness of vertical dimensions in the atmosphere as compared with the horizontal dimensions makes it difficult to allow that there is really room for an effective vortex with a horizontal axis. ”

“ Some controversy was excited by the publication of Aitken’s views, and it is interesting to revert to it because it illustrates a proposition which is of general application in meteorological questions, namely, that the physical processes operative in the evolution of meteorological phenomena are generally complex. ”

“ Soon elected to a fellowship, he accepted, owing to weak health and with a view to avoiding the climate of England, the professorship of mathematics at the Engineering College at Roorkee in the North-West Provinces, under the Indian government. ”

“ The observations at Kew observatory show that the electrical potential is abnormally high during fog, but whether that is the cause or the result of the presence of the water particles, we are not yet in a position to say. It must be remembered that a fog cloud ought to be regarded as being, generally speaking, in process of formation by mixing. ”

“ The pressure changes are continuous in the old layer and in the new layer, but discontinuous with varying degrees of discontinuity along the line of junction, where instability of the upper air may be set up. ”

“ Over the sea fog is most frequently due to the cooling of a surface layer of warm air by the underlying cold water. The amount of motion of the air must be sufficient to prevent the condensation taking place at the sea surface without showing itself as a cloud. ”

“ The line of advance of a line squall is generally from some point between south and north on the western side, the change of wind being from a warm southerly or westerly wind to a colder westerly or northerly one. ”

“ In 1874 he migrated to Calcutta as professor of physical science in the Presidency College and meteorological reporter to the government of Bengal. In 1886 he succeeded Henry Francis Blanford [q. v. Suppl. I] as meteorological reporter to the government of India and was appointed in addition director-general of Indian observatories in 1899. Eliot completed the organisation of meteorological work which Blanford began. ”

“ The excursions of the sun to the north and south of the equator are limited by the tropical circles, and the solar record on the hemispherical bowl will be confined within a belt 23° 27′ north and south of the plane through the centre parallel to the equator or perpendicular to the polar axis. ”

“ In North America, values exceed 3250 hours per annum in the New Mexico region. For other parts of the world the information available is not sufficiently extensive for the construction of charts. Eject upon Sunshine Records of the Smoke of Great Cities.—Much discussion has taken place from time to time as to whether the climate of a locality can be altered by artificial means. ”

“ They comprise a sudden increase of wind with a veer of direction of 45° to 90 , a sudden rise of pressure known in France as the crochet d'orage, and in Germany as the Gewitter Nase, a pronounced and permanent fall of temperature, and a shower of rain, hail or snow. While these various phenomena are indicated all along the advancing line their intensity may be very different at different points along it. The squall often exhibits greater violence in the middle portion, and it becomes more intense as the whole line advances. ”

“ As a climatological factor of the locality the shadow cast by the surrounding hills is of importance, it is part of the difference between the fertility of the southern and northern slopes of hill country. ”

“ Fig. 6 shows the average duration of bright sunshine for each hour of the day for each month at Valencia. The expectation of sunshine is greatest at I p.m. and 2 p.m. in May, while there is a well-marked secondary maximum in September.
ExPOS14f¢.-We now consider what the daily sunshine record for; particular station means. An ideal exposure has an uninterrupted view of those parts of the
horizon in which the sun rises or sets; Further, fig. 9 represents the average weekly distribution of sunshine in different sections of the British Isles according to the average of twenty-five years. ”

“ In these circumstances it 55° 237 265 276 363 418 494 510 511 456 376 319 245 218 becomes a question whether the amount 56° 232 263 273 362 420 499 516 516 459 376 316 239 2 1 1 of sunshine recorded should be referred 57° 226 260 270 362 423 504 524 523 463 377 314 236 205 to the maximum possible for an un- 58° 219 257 267 361 426 510 532 530 467 378 312 232 197 interrupted horizon or the maximum 59° 211 253 263 361 429 517 541 538 471 379- 309 225 187 possible for the particular exposure. The answer to the question really depends upon the purpose for which the information is wanted. ”