PROGRESS OF METEOROLOGY IN 1889. 247 



two minima, with an amplitude varying" from 0.079 to 0.2 millimeters. 

 But opposed to these are the observations of Laplace on the variations 

 of the barometer at Paris, as also of Kreil in Prague, and Bessel's 

 observations on atmosphere refraction. All these last-named observers 

 found that the action of the moon on the earth's atmosphere is either 

 nil, or else the reverse of that described. Professor Bornsteiu then 

 discussed the question whether any ebb or flow of the atmosphere could 

 possibly be detected by the means at our disposal, and showed that the 

 mercurial barometer can never give indications of such action, since it 

 is itself affected by the alterations of gravity that are due to the vary- 

 ing" j)Osition of the moon. He explained the phenomena observed at 

 the four stations mentioned above as due to the fact that they are 

 situated on the sea-coast at places on the earth's surface where the ebb 

 and flow of the sea is very considerable. The barometric effect is, 

 then, a secondary one, due to the changing position of the sea-level. 

 {Nature, xxxix, p. COO.) 



Charts of barometric pressure. — The Meteorological Council nave pub- 

 lished charts showing the mean barometric pressure over the Atlantic, 

 Indian, and Pacific Oceans. These are issued in the form of an atlas, 

 and give in a very complete manner the barometric means and rain 

 over all oceans. Separate charts are given for February, May, August, 

 and November, which are selected to represent the characteristic dis- 

 tribution of pressure for the respective seasons. The number of observa- 

 tions used in the preparation of the charts is, for the Atlantic Ocean, 

 339,300; Indian Ocean, 163,000; Pacific Ocean, 88,300. The baro- 

 metric means are given for areas of 5 degrees of latitude by 5 degrees 

 of longitude in large figures, and in smaller figures are given the mean 

 for areas of 2 degrees in latitude and longitude, the several means being 

 obtained from the daily averages ; the isobars are given for each teuth 

 of an inch. The general charts which give the isobars of the globe 

 show very clearly the prevalence of high pressure areas in each ocean 

 in each of the four seasons ; it is seen that these areas oscillate in posi- 

 tion and alter somewhat in intensity with the seasons, but there are 

 many characteristics iji common. The Northern Indian Ocean, which 

 is much more surrounded by land, is however an exception, the high 

 pressure being situated over the northern part of the ocean in Novem- 

 ber and February and decreasing southwards, whilst in May and August 

 the pressure is lowest in the north and increases southwards, this change 

 being closely related to the monsoon winds. These charts are consid- 

 erably in advance of any previous work of a similar nature, and will 

 materially aid in explaining the general circulation of the wind over 

 the globe. [Nature, xxxviii, ]). 190.) 



Diurnal variation of the barometer. — Mr. Henry F. Blanford has made 

 an important study of the relations of the diurnal barometric maxima 

 to certain critical conditions of temperature, cloud and rain-fall. The 

 author has re-examined the suggestion made by Espy (1840) and Kreil 



