1046 



INDEX. 



in its orbit, probable cause of periodic 



change, 944. 

 Magnetic forces, the thermal separable 



from the ten-estrial, 730. 

 Magnetic elements of any place deducible 



from the thermal elements ; derivable 



by simple formulae, 730; horizontal and 



vertical intensity of, 730. 

 Magnetic inclination and force in Nova 



Scotia and INew Brunsvrick, 751. 



intensity, maximum point of, 623. 



'- meridian, cause of the needle rest- 

 ing in, 626. 

 Magnetic needle, diurnal variation of, 



alternate in the northern and southern 



hemispheres, 664. 

 , distm'bed by aurora borealis, 



791. 



Magnetic observations at Prague and 



Milan, 475. 

 survejing expedition, account of, 



596. 



curves registered bv photographv, 



630. 



survey of the Indian Archipelago, 



908. 



Magnetic variation, in the Atlantic Ocean, 

 map of, for 1840, 835; its changes 

 more rapid than those in the iron of a 

 ship while changing her geographical 

 position; variable corrections to be 

 appUed, 836. 



' , method of registering, 630, 



658, 851. 



Magnetism, influence on light and mat- 

 ter, 569. 



, cause of discrepancies in the Ca- 

 vendish apparatus ; nature of its influ- 

 ence, 668. 



, terrestrial, on ; its principle con- 



fined to the earth's surface, 730. 



■ , influence of, on polarized light, 741. 



, direct production of heat by, 826 ; 



molecular friction inferred ; magneto- 

 electric heat ehminated; no thermic 

 effects with silico-borate of lead and 

 non-magnetic metals ; nickel and co- 

 balt develope heat in proportion to 

 their magnetic intensity, 826. 



, mathematical theory of ; hypothe- 

 sis of two fluids improbable; coinci- 

 dence of formulae with those of Poisson, 

 845. 



. , mathematical theory of, 975. 



Magnetisme terrestre,les causes du, prou- 

 vees, 978. 



Magnetism, atmospheric, 998; aiTange- 

 meut and action of lines of magnetic 

 force in space ; conduction polarity ; 

 different efi'ects of oxygen and ni- 

 trogen ; of temperatm'e ; movements 



of the needle aflfected by the course 



of the sun, 999 ; corresponding effects 

 at Hobarton and Toronto; probable 

 centre of action; hues of magnetic 

 force influenced by winds, rain and 

 snow ; movement of cmTents of air by 

 magnetic force, 1000; representation 

 of the phenomena by magnetic appa- 

 ratus ; coincidence of results ; effect of 

 cold air on magnetic lines, 1001. 



]Magneto-, and magnecrystalhc force ; its 

 action on cn,'stals of bismuth, 780 ; of 

 antimony, arsenic, osmium, tellmium, 

 titanium, iridium, iron, nickel and 

 others ; results with different metals ; 

 effect of extra magnets on, 781 ; na- 

 ture and difference of ; not referable to 

 polarity, 782. 



Maguetograph, 663. 



Magnetometer, scale and temperatm'e co- 

 eflicients of the force of, 852. 



Magnetometers, and meteorological in- 

 struments, automatic registration of, 

 657. 



Magnets, precautions to be observed in 

 their use in correcting ships' com- 

 passes, 750. 



Mammalia, structure and development of 

 liver in, 694. 



Man, temperature of, 564. 



, muscular power in, 691, 760. 



, temperature of, within the Tropics, 



946 ; higher than in a temperate cli- 

 mate ; fluctuations of, reversed ; effects 

 of exercise, of sea sickness and a sea 

 voyage, 947. 



Mantell (G. A.) on the fossil remains of 

 the foraminifera, discovered in the 

 chalk and flint of the south-east of 

 England, 627. 



, observations on some Belemnites 



and other fossil remains of cephalo- 

 poda, discovered in the Oxford clav, 

 &c., 746, 920. 



on the structure of the jaws and 



teeth of the Iguanodon, 757. 



, additional observations on the 



osteology of the Iguanodon and Hy- 

 Iseosam-us, 804. 



, royal medal awarded to, 872. 



, supplementary observarions on the 



structure of the Belemuite and Belem- 

 noteuthis, 920. 



on the Pelorosaurus, an undescribed 



gigantic terrestrial reptile, whose re- 

 mains are associated with those of the 

 Iguanodon and other saurians, in the 

 strata of Tilgate Forest, 921. 



on a dorsal dermal spine of the 



Hylaeosam-us recently discovered in the 

 strata of Tilgate Forest, 957. 



