602 



Epidermis of plants, on the probable 

 origin of the, 303. 



Errors, on the hiw of, 350, 



Fibre, spiral, on the formation of cells 

 fiom, 290. 



Forbes, J. D., on the polarization of 

 heat, 148, 173; on the depolariza- 

 tion of heat, 179. 



Galvanic circuit, mathematical inves- 

 tigation of the, 40 1 ; influence of 

 the atmosphere on, 472 ; chemical 

 changes in, 488. 



Galvanometer for magneto-electric 

 experiments, construction of a, 3. 



Gauss, C. F., on the observations made 

 by the Magnetic Association in 1836, 

 20 ; on the method of making mag- 

 netical observations, 42 ; on daily 

 observations of magnetic declina- 

 tion made at Gbttingen, 54 ; on a 

 general theory of terrestrial mag- 

 netism, 184, 313 ; on a new instru- 

 ment for the direct observation of 

 the changes in the intensity of the 

 horizontal portion of the terrestrial 

 magnetic force, 252 ; on the reci- 

 procal action of two magnets at a 

 great distance, 270. 



Goldschmidt, Dr. B., on the magnetic 

 observations at Gbttingen, 589. 



Gbttingen, description of the Mag- 

 netic Observatory at, 20 ; magnetic 

 observations at, 589. 



Graliam, Prof., on setherification, 

 386. 



Heat, on the polarization of, 141 ; on 

 the quantity of, radiated by different 

 bodies under a serene sky at differ- 

 ent hours of the day, 164. 



Heights, on the barometrical mea- 

 surement of, 517. 



HorkeljM., on the occurrence of spiral 

 fibrous cells in certain plants, 293. 



Instruments, descriptions of magneti- 

 cal, 25, 262. 



Intensity, magnetic, observations on, 

 214; on a new instrument for the 

 direct observation of the changes in 

 the, 252. 



Iron, peroxide of, on the separation 

 of, from cobalt, nickel, and other 

 metals, 385. 



. , soft, on the magnetic power of 



hollow tubes constructed of, 1 ; on 

 the limits of the magnetic power 

 which soft iron is capable of ac- 

 quiring, 7. 



Jacobi, H., on the application of elec- 



tro-magnetism to the movement of 

 machines, 1. 



Kane, Dr., on the compounds of am- 

 monia, 562. 



Light, on the polarization of, 159. 



Machines, on the application of elec- 

 tro-magnetism to the movement of, 

 1. 



Magnetic Association, results of the 

 observations made by the, in 1836, 

 20; in 1839, 587. 



declination, daily observations 



of, at Gbttingen, 54, 567, 589. 



fluids, on the measurement of, 



188. 



Observatory at Gbttingen, de- 

 scription of the, 26 ; results of ob- 

 servations at, 589, 567. 



- power of soft iron tubes, experi- 

 ments on the, 1. 



Magnetical observations, on the me- 

 thod of making, 42. 



observatories, remarks on the 



arrangement of, 25. 



Magnetism, distribution of, in hollow 

 cylinders, 4. 



, terrestrial, on the irregular vari- 

 ations of, 20 ; description of a small 

 portable apparatus for measuring 

 the absolute intensity of, 65 ; gene- 

 ral theory of, 184, 313; on anew 

 instrument for the observation of 

 the changes in the intensity of the, 

 252. 



Magneto-electric currents, duration of, 

 11; propagation of, 11. 



Magnetometer, construction of the, 30. 



, Bifilar, on the arrangement and 



use of the, 268 ; transportable, 

 565. 



Magnets, on the i-eciprocal action of 

 two, at a great distance, 270. 



Marchantise, on the germination of 

 the spores of the, 300. 



Melloni, M., on the polarization of 

 heat, 141. 



Metals, on the conductibilities of, for 

 electricity, 426. 



Meyen, Prof. J., on the import of 

 starch in plants, 285 ; on the forma- 

 tion of cells from spiral fibre, 290. 



Meyer, E., on the growth of plants, 

 298. 



Mica, polarization of heat by, 142 ; on 

 the preparation of, for experiments 

 on polarization, 149. 



Mirbel, De, on the formation of cells 

 in plants, 282. 



