398 



Napierian Logarithm of 5 = 



1-6094379 

 9525601 

 5759268 

 5124170 



6314333 

 3804931 



^•3025850 



7601 lOI 



8513707 

 3350481 

 I4I5335 

 7784979 



1243410 



3542685 



0738412 



8082338 

 5570584 



0408586 



0374600 



I772I9I 

 2078288 

 1773353 



1878072 

 I45I680 



7593332 



2646780 



5798574 



3644800 



7874564 

 3463508 



Napierian Logarithm of 10 = 



9299404 

 4886287 

 3005047 

 2381057 

 9829761 

 7747709 



5684017 

 7297603 

 7285093 

 6355463 

 8312394 

 8399376 



9914546 

 3326304 

 14007 1 1 

 4093686 

 5299109 

 1744515 



2618763 



8257554 

 2982618 

 7450601 

 5612567 

 54+&C. 



8436420 

 4104637 

 3354530 

 9182209 

 9105717 

 35+&C. 



Modulus of Common System of Logarithms = 



•4342944 8190325 1827651 1289189 1660508 



2294397 005S036 6656611 4454084 2952103 



2056138 9388912 2647096 6953461 1420043 



3938056 4705613 4312230 2306044 2927744 



1521725 4737266 8184290 1672329 4707564 



5865061 2932297 5502468 4291564 99-j-&c. 



The foregoing values are, it is presumed, correct to the last figure 

 inclusive. 



February 9, 1854. 



SIR FREDERICK POLLOCK, M.A., V.P., in the Chair. 



A paper was in part read, entitled " Further researches into the 

 properties of the Sulphate of lodo- Quinine or Herapathite, more 

 especially in regard to its Crystallography, with additional facts 

 concerning its optical relations." By William Bird Herapath, M.D. 

 Communicated by Golding Bird, M.D., F.R.S. Received Jan. 27, 

 1854. 



February 16. 1854, 

 COLONEL SABINE, R.A., Treas. and V.P., in the Chair. 



Joseph Beete Jukes, Esq., was admitted into the Society. 



The reading of Dr. Herapath's paper was resumed and concluded. 



After referring to the observations of Professors Stokes and Hai- 

 dinger, as well as to papers already published by himself on this 

 subject in the Philosophical Magazine, the author gives an account 

 of a set of prisms perfectly complementary in their optical characters 

 to those previously described by him, and proves this fact by an ela- 

 borate comparison of their various optical relations ; from which it 

 appeared, that whilst the a-prisms (those described in Philosophical 

 Magazine for March 1852) were totally impervious to a beam of 

 polarized light, reflected from glass plates, when the plane of the 

 length of the prism was at right angles to the plane of primitive 

 polarization, the /3-prisms (those now examined) were equally ab- 



