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The astrometric observations made at the Cerro Calán observatory with several instruments since 1962 are outlined. The resulting catalogues are in press or approaching publication, and are described in some detail. An account is given of the observational projects currently in progress.The various catalogues are combined in order to demonstrate the large and well-determined systematic differences in Δαδ cosδ between the Cerro Calán observations and the FK4. It is concluded that the FK4 system requires some improvement if it is to fulfil the requirements of a fundamental reference system in the southern hemisphere.

During almost every winter anti-cyclone, with its accompanying cold but calm and fair weather, the temperature at Fort-William is, for part of the time, nearly as low or lower than that on Ben Nevis, 4400 feet above it. The average difference of temperature is 16° Fahr.; Ben Nevis being that much colder, or about 1° for every 270 feet. But in anti-cyclones this normal difference of temperature is widely departed from, the records showing that Ben Nevis has been 17° warmer instead of 16° colder than Fort-William, a departure of 33° from the normal; and it has frequently been 5° to 10° warmer for a day or two at a time. These data only give the temperatures on the summit of Ben Nevis, and at the sea-level five miles away they give us no information as to what it is in the intermediate air. That there is something unusual in this 4400 feet of atmosphere is hinted at by two facts,—first, with this abnormal temperature arrangement we always have very dry air on the summit, and very damp air at Fort-William; second, the difference of the barometer readings at top and bottom is less than the normal difference for the temperature. The former is an inversion of the ordinary humidity conditions—usually the air on the summit is saturated, or nearly so, with moisture, and at Fort-William dry; the latter, the barometric differences, require a few words of explanation to show what exactly they indicate, and how they bear on the question of temperature.

The observations detailed in this paper are similar to those described by the author in his former papers, and the results deduced from them agree generally with those previously obtained. In the introductory remarks, the author states that he determined the heights of the different rain-gauges above the level of the sea by means of an excellent Aneroid barometer (previously compared with a standard), and a standard barometer read simultaneously, or nearly so, at the sea-level; and he gives the heights of the several stations as thus estimated.

In the September 1962 issue of this journal, professor Riehl presented some conclusions from an atmospheric infrared study [Riehl, 1962]. I am in complete agreement with his conclusions and certainly do not wish to contest them, but I would like to add some comments. In this radiation study it was observed that the upward- and downward-streaming radiation fluxes occasionally exhibited sharp changes at high levels (in the vicinity of the 300-mb level). Riehl states: ‘The atmospheric constituents, or aerosols, producing such sharp changes of standard deviation in the upward and downward radiation streams have not been observed directly... . We postulate either presence or absence of cirrus sheets spread over the lower cumulus sky’ This postulate is unquestionably correct; the fact that cirrus have the property of producing enormous attenuations of the atmospheric radiation streams was experimentally verified quite clearly some years ago.

In a recent paper in this journal [Moore, Vonnegut, Stein, and Survilas, 1960], a number of observations of lightning in warm clouds, all parts of which were above freezing temperatures, were presented to support the concept that intense electrification responsible for lightning is not caused by the presence of ice in the clouds. Since all the observations were from the tropical or subtropical environment, a similar observation from temperate latitudes would be significant. I should like to quote (translated by me from the French) an early observation of lightning inwarm clouds, all parts of which were above freezing temperatures, published by Marchand [1903], a report which apparently has escaped the attention of recent meteorologists. The statement is of particular interest since it was based on observations made in the temperate zone, at Bagneres (a town located at 547 meters elevation at the foot of the Pyrenees Mountains in southern France) and at the Observatory on Pic du Midi (42°56′N, 0°08′E, at 2866 meters in the Pyrenees)

Figures 4 and 6 of the paper [Palmer, 1959] illustrated the time variation of atmospheric pressure, temperature, and density at two stations in the core of the vortex prior to and during the warming of the arctic stratosphere in 1958. Since that time, the entire polar cap has been analyzed, using the complete IGY data at the 15-km level, to determine the daily distribution of these same variables. The map series from January 11 through January 30 is presently being prepared for publication.1 The influence of the land and sea distribution is manifest in the asymmetry of the stationary features on the maps.

In a paper recently published in this Journal E. G. Bowen (1953) has proposed that meteoritic dust is an important factor in stimulating rainfall. This hypothesis is advanced as a result of a study of daily rainfall statistics .over a long period for Sydney and other places which reveal features, it is claimed