Notices respecting New Books. 227 



general, particularizing the hours whose temperature agrees with 

 that of the mean for diiferent places. 



The fourth traces the direction of isothermal lines ; speaks of the 

 mean annual temperature at various places ; and gives a curve of the 

 mean monthly temperature at Greenwich, deduced from the obser- 

 vations taken at the Royal Observatory in the years 1841, 1842, 

 1843 and 1844, but which curve differs from the numbers at the 

 foot of the diagram. The numbers are correct. In this chapter 

 the effects of heat and cold are treated, and many interesting anec- 

 dotes are mentioned. 



The fifth speaks of the colour of the atmosphere, of refraction, 

 twilight, polarization of light, &c. 



The sixth treats of evaporation and vaporization. 

 The seventh treats of dew and radiation of heat, particularizing the 

 experiments of Dr. Wells, but mentions no subsequent English ex- 

 periments ; of mists, fogs and clouds. 



The eighth is employed upon rain, in considerable detail. The 

 ninth is devoted to the consideration of hail, snow, glaciers, &c. The 

 tenth to the rainbow, and to all the phsenomena connected with the 

 cirrostratus cloud. The mirage is the principal subject of the eleventh, 

 and lightning that of the twelfth. The thirteenth chapter relates to 

 meteors in general. The fourteenth to the aurora borealis and to 

 magnetism. The fifteenth treats of the direction and strength of 

 the wind. The sixteenth is occupied by particulars respecting the 

 simoom and the sirocco ; the seventeenth by whirlwinds, great storms 

 and hurricanes ; and the eighteenth by popular prognostications of 

 the weather. 



In each chapter a great number of instances of the class of phseno- 

 mena is collected. Such are the parts of this work ; and we cannot 

 doubt that the public will receive it with favour. It is amusing ; 

 there are many interesting anecdotes interspersed ; it is written in a 

 pleasing style ; and great taste has been exhibited in the aptness and 

 beauty of some of the poetic quotations. 



The chapter on instruments, which appears as an appendix, is the 

 least interesting and satisfactory portion of Dr. Thompson's work. 



The account given of the barometer is merely popular ; and the 

 sketches given of this instrument do not include that of a standard. 

 A large space is devoted to the aneroid barometer ; which, beautiful 

 as it is for domestic and ordinary purposes, is totally unfitted for 

 meteorological or experimental inquiry. Dr. Thompson gives the 

 impression that the aneroid barometer is as accurate in its indications 

 as a perfect mercurial barometer ; in fact, says that the mean differ- 

 ence of the readings of the two, from 109 simultaneous comparisons, 

 is only two-thousandths of an inch, this result being deduced from 

 the observations published by Mr. Dent on the aneroid barometer. 

 But Mr. Dent in his pamphlet only asserts that the comparisons 

 were made with two of the most expensive and perfect mercurial 

 barometers ; neither of which is described or again mentioned. The 

 readings by these barometers do not seem to have been corrected for 

 temperature ; so that the near agreement of the readings only indi- 



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