256 Capt. Newbold on a recent Fossil Freslmater Deposit in 



Halley did that of Newton in the case of the Principia; and 

 nothing but circumstances which made it more convenient to 

 print it at Nuremberg than at Wittemberg, prevented the 

 name of Rheticus from appearing in the title-page as editor. 



*5i«* Mr. De Morgan requests us to append the following 

 remark to our reprint of his paper. 



The mode of defining the sine, cosine, &c., which is now 

 becoming common, and which, as appears above, was pre- 

 ferred by Rheticus, was first advocated in modern times by 

 Dr. Peacock. In the second volume of his Algebra, just pub- 

 lished (page 157, note). Dr. Peacock remarks "the definition 

 in the text, which is now exclusively used (see Hymer's Trigo- 

 nometry, Cambridge, 1837), was first formally introduced into 

 my Algebra (Cambridge, 18S0), and afterwards into a Syllabus 

 of a course of Lectures on Trigonometry (Cambridge, 1833)." 



The fact, however, as to iwinted publication, is, that the 

 system in question first appeared in Lardner's Trigonometry, 

 though Dr. Peacock is not the less the reviver of it. In the 

 first edition of Dr. Lardner's work (1826), the definition by 

 raiios is given^ but not used, the old ones being also given. 

 Thus the formula; for the sines and cosines of sums, &c. of 

 angles are deduced from the old definitions. Thus it is said 

 (p. 42), that " from the definition of the sine of an angle or 

 arc it appears that twice the sine of any arc is the chord of 

 double that arc." But in the second edition (1828) the for- 

 mulae are consistently deduced from the definition by ratios. 

 This was done at my suggestion, as noted in the preface, and 

 I was indebted for the idea to Dr. Peacock, who had taught 

 it at Cambridge for some years previously. — A. De Morgan. 



LXXIV. Note on a recent Fossil Freshwater Deposit in South- 

 ern India, nioith a few remarks on the Origin and Age of the 

 Kiinker, and on the supposed decrease of Thermal Tempera- 

 ture in India. By Capt. Newbold, M.N.I. Assistant Mesi- 

 dent, Kurnool, Madras Territo7-7/*. 



THHE geographical locality of this deposit is in the Kurnool 

 -■■ territory, about a miie easterly from the village of Lun- 

 jabunda, in about latitude N. 15° 30' and longitude E. 78° 3'. 

 It lies in a jungly defile, or transverse valley, crossing the 

 range of hills which, running nearly north by east and south 

 by west, divides Kurnool into two portions. This range com- 

 mences about five miles south of the city, and after traversing 



• From the Journal of the Asiatic Society of Bengal, N. S., 1844. No. 64. 



