Miscellanies. 201 



their common centre of gravity, we shall be able also to determine the 

 sura of their masses. I have attentively considered the preceding obser- 

 vations of the relative positions ; but I consider them as yet very inade- 

 quate to afford the elements of the orbit. I consider them sufficient only 

 to show that the annual angular motion is somewhere about | of a de- 

 gree; and that the distance, at the beginning of this century, had a min- 

 imum of about 15". We are enabled hence to conclude that the time of 

 a revolution is more than 540 years, and that the semi-major axis of the 

 orbit is seen under an angle of more than 15". If, however, we proceed 

 from these numbers, which are merely limits, we find the sum of the 

 masses of both stars less than half the sun's mass. But this point, which 

 is deserving of attention, cannot be established until the observations shall 

 be sufficient to determine the elements accurately. When long continued 

 observations of the places which the double star occupies amongst the 

 small stars which surround it, shall have led to the knowledge of its cen- 

 tre of gravity, we shall be enabled to determine the two masses separ- 

 ately. But we cannot anticipate the time of these further researches." 



28. Ornitliology of the United States, the descriptive part by J. K. 

 Townsend; the drawings from nature by French artists, Philadelphia, 

 published by J. B. Chevalier, 1839, Vol. I., part 1, large 8vo. 



The prospectus states that this work will be published in monthly parts, 

 and each part will contain four plates, or eight birds, with sixteen pages 

 of descriptive matter. Twelve numbers will complete a volume of forty- 

 eight plates, or ninety-six birds, with two hundred pages of letter press. 

 Five volumes will complete the work, the price, one dollar and twenty- 

 five cents each number, or about $60 for the work when complete. 



The figures are reduced, and not drawn or colored in the highest style 

 of lithographic plates, but sufficiently well for all purposes of the ornithol- 

 ogist. The text is simple and unaffected, and the descriptions accurate. 



29. Third American from the fifth English edition of BahevjelVs Ge- 

 ology. — In our last number, (Vol. xxxv. p. 385,) we mentioned the new 

 American edition of Bakewell's Geology, by B. & W. Noyes, of New 

 Haven. The entire work extends to 598 pages, 8vo., of which the ap- 

 pendix by Prof Silliman, occupies 122 pages. 



There are nine plates, six of which are folded, and more than thirty 

 wood cuts. 



This American edition is printed with a large clear and legible 

 type, and upon white paper. American paper, as it appears partic- 

 ularly in the reprints of foreign works, is still decidedly inferior to 

 English paper, both in the quality of the material and the firmness 

 and beauty of. the fabric. If, however, we look back a few years, we 

 find the English paper, especially in their common and periodical works, 



Vol. XXXVI, No. 1.— Jan.-April, 1839. 26 



