132 Reviews, and Notices respecting New Books. 



labours of meteorologists to those subjects of investigation afforded 

 by the atmosphere and its various attributes and relations, to which 

 it is now indispensable, in order to impart a truly scientific form to 

 Meteorology, that their combined and methodical attention should 

 be directed. Consisting, however, almost entirely, of minute de- 

 tails, it is not susceptible of abridgement : we shall therefore con- 

 fine our notice of it to extracting the " contents," together with a 

 notice of the results of the author's own investigations relative to 

 the horary oscillations of the barometer, of which no previous ac- 

 count has been given in the Philosophical Magazine. 



The following are the "contents" of the Report: — 



"Introduction, Discoveries on Heat; Systematic Works on Meteorology. 

 Constitution of the Atmosphere. Temperature, Thermometers; Atmosphe- 

 ric Temperature; Climatology; Decrease with Height; Proper Tempe- 

 rature of the Globe. Atmospheric Pressure, Barometers ; Periodical Va- 

 riations ; Accidental Variations ; Variation with Height. Humidity, Hygro- 

 meters ; Distribution of Vapour in the Atmosphere. Atmospheric Phceno- 

 mena and Precipitations, Winds; Rain; Atmospherical Electricity, Hail; 

 Aurora Borealis, its Influence on the Magnetic Needle." 



Mr. Forbes sums up the results he has obtained with respect to 

 the horary oscillations of the barometer, in the paragraphs now sub- 

 joined. 



" In 1828 I published some observations made by myself at Rome the 

 previous year*. Though continued only for a short time, yet, as I fre- 

 quently made twelve or fourteen observations in a day, I was enabled to 

 trace out very well the diurnal curve of variation, establish the critical hours 

 of morning and evening maxima and afternoon minimum, and give an ap- 

 proximation to the amount. 



" Since that, I have investigated with great care, during the years 1827-30, 

 the oscillation in latitude 56°, — the most northerly point in Europe at which 

 any observations of long continuance on this subject have been made. The 

 results have been published at length in the Edinburgh Transactions f ; and 

 I have also entered into an analysis of all the existing information on the 

 subject. The following are the general results at which I have arrived. 



" 1st, That near Edinburgh, in lat. 56°, the mean annual oscillation be- 

 tween 10 a.m. and 4 p.m. is -0106 inch, or O mm -27. 



" 2nd, That the hours of maxima are further from noon in spring and 

 summer than in autumn and winter ; and that the amount of oscillation of 

 both the diurnal periods diminishes regularly through the seasons from 

 spring to winter. These conclusions, derived directly from my own ob- 

 servations, I have shown to be the most probable for all parts of the globe, 

 as far as existing observations guide us. 



" 3rd, That the St. Bernard observations, and those of Captain Parry in 

 the arctic regions, both indicate a true negative oscillation, though the 

 second result has been overlooked by M. Bouvard. 



" 4th, That M. Bouvard's hypothesis and formula mentioned above, are 

 founded upon too hasty generalization. This I have shown upon various 



r 



* Edinburgh Journal of Science, January and April 1828. 



f Vol. xii. The title of the paper is, " On the Horary Oscillations of the 

 Barometer near Edinburgh, deduced from 4410 Observations ; with an In- 

 quiry into the Law of Geographical Distribution of the Phenomenon." An 

 abstract has been printed in the Edinburgh Journal of Science for April 

 1832. 



