Bibliography. 305 



Sun and the conditions of the atmosphere may admit. Owing to the 

 absence of stars of sufficient magnitude within 15° of the Sun, an 

 omission is made in the Ephemeris during the time that the planet will 

 be within that distance of the Sun. It is proposed, during such inter- 

 vals, to rely exclusively on meridian observations, both at The Observa- 

 tory in Chile and elsewhere. 



The precise place in Chile, at which the Observatory is to be erected, 

 will not be decided upon until the arrival there of the Expedition. 



Those Astronomers, who are disposed to forward the objects of the 

 Expedition so far as to cooperate with it in conducting an auxiliary 

 series of observations, will perceive that the results of their labors will 

 be enhanced by using, whenever practicable, the stars of comparison 

 which Lieut. Gilliss has selected, and which are given in tables 1 and 

 2, and by following generally the plan of observations proposed by him 

 and herein explained. Each co-laborer is requested to send annually, 

 to the Superintendent of the National Observatory, at Washington, his 

 observations, with an account of the instruments with which they were 

 made, together with such other information in relation thereto as is 

 necessary to a full understanding and appreciation of them and the re- 

 sults arising therefrom. 



6. Introduction to Meteorology ; by David Purdie Thomson, M.D., 

 Grad. Univ. Edinb., Licent. Roy. College of Surgeons, Edinb. 486 pp. 

 8vo. Edinburgh and London. 1849, Wm. Blackwood & Sons.— The 

 work on Meteorology by Dr. D. P. Thomson, ranges over the whole 

 held of meteorology in its widest sense, including the general characters 

 of the atmosphere, chemical and physical, barometric, thermometric and 

 hvgrometric, as well for heights as for the ordinary level, and for all 

 zones. The causes of the distribution of temperatures are considered 

 the color of the atmosphere — various properties of light — clouds, 



their many details, even lo 

 and " Blood spots ;" — also 

 m, rage, and lightning in all its varieties of action and effects; — meteors 

 and their theories and supposed agency; — auroras, and other lights to 

 the u ig n , s dtutm" — winds and their theories; and descripiions of 

 various instruments for meteorological observation. There is in some 

 de partmen!s a want of system in the presentation of the facts and of dis- 

 crimination in their selection and condensation, which interfere with the 

 scientific value of the work,— a defect which may however increase 

 ItJ * popular inierest. The chapter relating to winds abounds in the 

 wonderful, with too little true science. Various incidents are intro- 

 duced by way of illustration thai give variety to the subject treated, 

 a °d an excellent literary taste pervades the work. 



7 - A Memoir on the Geological Action of the Tidal and other Cur- 

 rents of the Ocean ; by Charles Henry Davis, A.M., Lieut. U. S. N. 

 "-From the Memoirs of the American Academy of Arts and Sciences, 

 ^ew Series, vol. iv, 40 pp., 4to, with three maps. Cambridge. 1849.— 

 No observations at the present time can better promote the progress of 

 geology than those relating to the tidal currents of the ocean and the 

 attribution of material thus produced : and science owes much to 

 jweut. Davis for the exposition of this subject which he has made. 

 u ur coast affords facts of a most extended and varied character, and 



Second Seri ES , Vol. VIII, No. 28.— Sept., 1849. 39 



4 ram and snow and all allied phenomena in 

 u Dust-rains," " Fish-rains," " Frog- rains," 



