410 Scientific Intelligence. 



a very delicate astatic needle was suspended. I did not observe any 

 distinctly appreciable effect at the moment at which I united or separa- 

 ted the extremities of the chain. Had an effect been obtained, the ob- 

 jection from the action of the heterogeneous moist parts would still 

 remain. 



It does not appear to me that the existence of electric currents in 

 frogs and plants is a perfectly proved fact. I speak openly, submitting 

 my doubts to those philosophers who have made most interesting, and 

 in some cases very ingenious experiments upon this subject. 



4. On the Polarization of Heat. — The polarization of heat first an- 

 nounced by Berard, has been established by various experiments by 

 Forbes and Melloni. Provostaye and Uesains have lately announced 

 to the Academy of Sciences at Paris, (Session of July 30,) new inves- 

 tigations showing 



(1.) That heat traversing Iceland spar is divided into two pencils, 

 completely polarized in the plane of the principal section or a perpen- 

 dicular plane. 



(2.) That the law ascertained bv Malus, according to which, the in- 

 tensity of a ray completely polarized is divided between the ordinary 

 and extraordinary images to which it gives origin in traversing the spar, 

 is applicable to heat as well as light. 



(3.) That the variations of intensity which polarized heat experiences 

 in its reflexion from glass at different incidences, are exactly repre- 

 sented by FresnePs formulas determined for light, only allowing that 

 the solar heat traversing the prism has a little different index — 1*5. 



(4.) That there is a most perfect correspondence between the phe- 

 nomena presented in the reflection from polished metals of polarized 

 heat and polarized light. 



5. Composition of Bones, (Acad. Sci. Berlin, Feb., 1849.)— M. W. 

 Heintz, finds for the phosphate of lime in bones, the composition 



* • 



R 3 P, instead of the hypothetical formula Ca 8 P 3 of Berzelius. He 

 obtained in his analyses 





Bones of the ox. 



Sheep. 



Human bones. 



Lime, . 



. 37-46 



4000 



37-89 37 51 



Magnesia, 



. 30 97 



0-74 



057 056 



Phosphoric acid, . 



. 27-89 



29-64 



28-27 2800 



Carbonic acid, 



. 310 



308 



2-80 2-81 



Water, fluorine and 

 organic matter, 



30 58 26-54 3047 3112 



100 00 100 00 10000 100 00 

 Supposing the acids and bases united, adopting the formula given 



Carbonate of lime, . 707 700 6-36 639 



Phosphate of magnesia, 209 159 123 1*21 



lime, . 58-30 62-70 6013 59 67 



Lime, .... 196 217 181 H2 



W subsmncei ne,0r8aniC ^ 30 ' 58 2654 30 ' 47 3H1 



100 00 10000 10000 10000 



