296 



NA TURE 



[Aug. 13, 1874 



is the month of greatest, and August of least velocity, the 

 former exceeding the latter by 75 per cent. In some instances a 

 storm-centre has remained stationary for twenty-four hours, and 

 in four cases it travelled 1,200 miles in that time. In one case 

 a speed of 57'5 miles per hour was reached. In April 1S73 a 

 storm-centre clianged its path 360° in 24 hours. Taking into 

 account the actual motion of a storm-centre from hour to hour, it 

 seems that a storm-path may have every possible.direction, and the 

 velocity of progress may vary from 15 miles per hour westward 

 to 60 miles per hour eastward. 



The fall of rain seems to have a decided mfluence in modify- 

 ing the course of a storm-path. The rainfall area is usually much 

 larger to the east of a storm-centre than the west, 500 miles 

 being the average length on tlie east side. There is a connec- 

 tion between the velocity of the storm's progress and the extent 

 of this rain area — for example, when the eastern extent is 100 

 miles greater than the mean (500 miles), then the hourly velocity 

 increased I4"9 miles beyond the mean (25'6), but when the east- 

 ern extent of the rain area is 100 miles less than the mean, the 

 hourly velocity of the storm's progress is diminished S'l miles. 



As to the direction in which the rain area is most extended, the 

 axes of the areas were compared with the storm-paths, and gave 

 this result, that the average course of a storm-path for twenty- 

 four hours coincides very closely with the position of the axis of 

 the rain area for the preceding eight hours. 



Prof Loomis says: "The progress of a storm eastward is 

 not wholly due to a drifling, resulting from the influence of an 

 upper current of the atmosphere from the west, but the storm 

 works its own way eastward in consequence of the greater pre- 

 cipitation on the eastern side of the storm. Thus the baromet ;r 

 is continually falling on the east side of the storm and rising on 

 the west side, in consequence of the flowing in of colder air on 

 that side." 



In order to trace the influence of the wind's velocity upon the 

 progress of storms, Prof. Loomis divides a circle into four 

 quadrants, and by an arrow in each, showing the average direc- 

 tion of the wind, it is .at once perceived tliat there is a strong 

 tendency of the winds inward to the centre of the storm ; but 

 the average direction in each quadrant differed from what it 

 would be if the wind revolved in a circle round the storm- 

 centre. 



The velocity is greatest in the west quadrant and diminishes 

 in the successive quadrants as we pass round the circle from 

 west by south to north. On each side of the storm's centre the 

 wind blows obliquely inward, and hence it is inferred that in the 

 central region of the storm there is an upward motion of the air, 

 and this is the cause of the precipitation of vapour ; that is, the 

 cause of the rainfall. 



The average rise of a barometer for twenty-four hours in the 

 rear of a storm is sensibly greatest when the velocity of progress 

 is greatest. Prof. Loomis believes it is possible to predict where 

 a storm-centre will be at the end of twenty-four hours. 



His inquiries into the relation between ihe velocity of the 

 wind and the velocity of a storm's progress have led to the con- 

 clusion that at a height of 6,000 ft. in the western quadrant of a 

 storm the velocity of the wind is 68 per cent, greater than the 

 velocity with which the storm advances. 



He then considers how to determine whether a storm is 

 increasing or diminishing in intensity, and concludes that when 

 the barometer rises more rapidly than usual as the storm passes 

 by, the pressure at the centre of the storm is increasing ; but 

 when in the rear of the storm the barometer rises less rapidly 

 than usual, the pressure on the centre is diminishing or the storm 

 is increasing in intensity. Sections on " The Form of Isobaric 

 Curves," on " The Classification of .Storms," and " Where do 

 the Storms which seem to come from the far west originate ? " 

 conclude the article. 



SCIENTIFIC SERIALS 



The Gcologkat Magazine, August. — This number contains five 

 original articles. i. Notes on fossil Orthoptera rel.ated to 

 Gryllacris, by A. H. Swinton. The fossil remains are two from 

 the eocene and three from the coal formation. The two eocene 

 are, Gryllacris Ungeri of Heer, and G. Cliarpcntieri oi Ileer. 

 The coal species are, Gryllacris lithaittliraca, two species, and 

 Gryllacris \_Corydalis\ Broiigiiiarti (Aud. ). In the specimen 

 G. Brougniarti there are indications of the "file," on which Mr. 

 Swinton remarks : " We see this ancient instrument of music had 



already attained to all appearance an efficiency at least thrice 

 that of our modern house cricket, and must have emitted notes 

 that rang widely over the tropical forests that clothed our island 

 in the old days of the coal period." — 2. On the Source of Vol- 

 canic Heat, by Mr. G. Poulett-Scrope. Four-and-a-half pages 

 are occupied in disavowing the views "saddled" upon him by 

 Mr. Mallet, and in saying that Mr. Mallet's " definition " is a 

 statement of a series of conjectures. — 3. On the Glacial Epoch, 

 by Mr. Croll. This is a continuation of the article commenced 

 last month. The probable thickness of the Antarctic ice-cap 

 was then considered, and now the results of the melting of a por- 

 tion of it are calculated. The Antarctic ice-cap is equal in area 

 to l-23'46 of that covered by the ocean ; therefore 25 ft. 6 in. 

 melted otf would raise the general level of the ocean one foot, 

 and one mile melted would raise the level 200 ft. Mr. Croll 

 takes for the time of his calculation the period when cold was 

 increasing in the northern hemisphere and warmth in the 

 southern. The lessening of ice-cap in the southern and an 

 accumulation of ice in the northern would displace the centre of 

 gravity of the earth leading to a rise in the sea-level in the 

 northern hemisphere. This, with the rise resulting from the 

 melting, Mr. Croll calculates M'ould give for the latitude of 

 Edinburgh a rise of sea-level of Soo to 1,000 ft. The suppo- 

 sition of the subsidence of land during our glacial period may 

 therefore, he argues, be dispensed with ; and he proceeds to 

 show how this theory avoids many difficulties which the ele- 

 vation and subsidence theory leads to. Further : the oscillations 

 of sea level resulting from the displacement of the earth's centre 

 of gravity throiv 'light on many obscure points connected with 

 the geographical distribution of animals and plants. For ex- 

 ample, during the warm periods the English Channel would 

 be dry land, and during the cold animals might cross to England 

 from the north upon a frozen sea. And still further : if we 

 knew (i) the extent of the general submergence of the glacial 

 epoch and (2) the present amount of ice in the southern hemi- 

 sphere, we could determine whether or not the earth is fluid in the 

 interior. — 4. Geological notes from the neighbourhood of Cairo, 

 by John Milne. Tne article, which is too long for us to notice, 

 is illustrated by a section and sketch maps. — 5. The Red Chalk 

 in Yorkshire, by the Rev. J. Y. Blake. The paper principally refers 

 to the occurrence ol Ammonites Desliaycsi in the red chalk, in the 

 pebble-beds below it, at Hunstanton, in the .Specton clay, and in 

 the gault of Folkestone. The chalk is a deep-sea deposit, and 

 in the sinking of the hind in Upper Cretaceous times the passage 

 beds from the Upper Neocomian to the Aptien were laid down 

 in various areas from various sources. A. Dcshaycsi evidently 

 lingered on during the time these changes were taking place till 

 the red chalk set in in Yorkshire and the gault at Folkestone. 

 — Among the reports is a notice of the Cotswold Club visit to 

 Bath aud a resume of a paper, read by Dr. Wright, On the 

 genesis of the oolites. 



Proceedings of Ike Liverpool Naturalists' Field Club, 1S73-74, 

 — This club, which is fourteen years old, we are glad to see con- 

 tinues in a flourishing condition as regards members and funds, 

 and has, during the session 1S73-74, been doing a fair amount 

 of work. The present number of the Proceedings contains the 

 address of the president, the Rev. H. H. Higgins, at the 

 annual meeting, in which he touches on a variety of topics 

 more or less connected with Natural History ; following this 

 is a list, prepared by Mr. Higgins, of all works bearing on the 

 Natural History of the district of Liverpool from 1705 to the 

 present time. The club made ten excursions during the 

 summer and autumn of 1873, and an account of these, with the 

 detailed results of some of them, occupies part of the number. 

 Appended is a list of excursion prizes to be competed for this 

 summer, and the names of last years' winners. 



Proceedings of the Winchester and Hampshire Scientific and 

 Literary Society, vol. I, partiii. (1872-3). — We learn from the 

 Fourth Annual Report of the society that as a consequence of 

 altering the rules so as to admit ladies, several ladies have 

 become members. We are glad to see also that sections have 

 been formed for the special study of botany, entomology, and 

 zoology, and that work has already been done in each ol these 

 departments. During 1S73, eighteen papers have been read in 

 the society, most of them on subjects connected with science. In 

 an introductory lecture, the Rev. E. Firmstone gives an inte- 

 resting resume of what is known about the ".Star Depths." 

 Among the other papers we would note an ingenious one On the 

 probable origin of flints, by Mr. A. Angell, jun. ; "The Heraldry 

 of the World, " a long paper, amply illustrated, by Miss Zomlin ; 



