300 Book Notices. 
a method of drawing tangents to curves very similar to that furnished 
by the calculus, before either Newton or Leibnitz had devoted any special 
attention to the subject. 
ndon: Tribner and Co. 1861. 512 pages, large quarto.—This vol 
ume contains the astronomical determinations of latitudes and longitudes 
and the magnetic observations made during the scientific journey of the 
brothers De Schlagintweit through India and High Asia. One 0 
chief objects of this journey was the completion of the magnetic survey 
of India, which had been commenced in 1846, by the late Captain Elliot 
in the Eastern Archipelago; but in consequence of the high interest 
evinced in it by the Directors of the East India company, the mission 
ro 
IX. Geographical aspects of India, the Himalaya, Tibet and — 
zontal intensity; the Dip and Vertical Intensity ; and a ne in 
intensity, The instruments employed were those generally ado ‘n 
the English magnetic surveys, and the magnetic intensity is expressed 
the unit employed by General Sabine, and other English philosophers. 
* See this Journal, vol. xxvi, 378, and xxix, 236. a 
a cn se 
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