remarkable intensity and brilliancy; if at the same time, the other end of the secondary wire is put in communication with one of the poles of the pile, a great increase takes place in the brilliancy of the spark. Then, on touching with the hand the iron core, and placing the free end of the wire in contact with the skin, a redness takes place, and a smart stinging sensation is felt. This last experiment was made upon a coil, the core of which, completely isolated in a tube of varnished glass, was eight millimètres in diameter. M. Rondel made the same experiment with another bobbin, the soft iron of which was twelve centimètres long, five centimètres wide, and eight millimètres thick. The sparks were produced with detonations. A single Bunsen element of small size was sufficient to produce these phenomena.

A note on the Polarization of Electrodes-a subject of considerable interest to telegraphists and electricians-has been presented by M. Gaugain to the Academy of Sciences. Several savants have sought to determine the part which each of the electrodes takes in the polarization, and have arrived at different results: M. Poggendorff found that the two electrodes contributed equally to the production of the electromotive force developed; MM. Lenz and Sarvelgen found, on the contrary, that the part of the cathode is greater than that of the anode. M. Gaugain has tried, in his turn, to resolve the question by making use, as he did on former occasions, of the method of opposition. The following are the results thus obtained by a series of experiments carried on with a mixture of nine parts by volume, of distilled water, and one part of sulphuric acid :

It appears to be of little consequence, if more or less sulphuric acid be added to the electrolyzed water, provided that this proportion does not fall below a certain limit; but when it becomes extremely small, the polarization of the cathode increases, without the polarization of the anode being sensibly modified. The following are the results obtained by electrolyzing pure water :

M. Matteucci recently called the attention of the Academy to an experiment which he made in 1838, and upon which he

*Comptes Rendus', Jan. 14, 1867.

depended to prove that the polarization proceeded from the gases adherent to the electrodes. In fact, polarized metals should be considered as fugitive combinations formed by the metals and gases, and the author is of opinion that in polarization couples as well as in Grove's gas pile the electro-motive force is the affinity exerted on one of the elements of the water by a gas associated in a particular manner with a metal.

Dr. Henry Morton, of the University of Penna, Philadelphia, has lately described an important adjunct to the induction coil. He prepares the arrangement in the following manner :-Take eight plates of glass, about 11 inches by 14 inches, and attach to both sides of each plate, sheets of tinfoil, 7 inches by 10 inches in size, with rounded corners. Set these plates upright in a box (provided with grooves for the purpose) about 1 inches apart; then rolling up some balls of paper large enough to fit between the plates, and wrapping a strip of tinfoil around each ball, thrust them between the plates, and, lastly, make an outside pole to the terminal sheets of foil, by means of wires enclosed in glass tubes passed through the side or top of the box. It is evident that we have here a compact form of Leyden battery, arranged for "cascade." With the ordinary electrical machine such an arrangement would be worthless, from its want of insulation. With the induction coil, however, which developes an entire charge in an instant, it becomes of great value in a certain class of experiments, because it gives us at once the concentrated charge peculiar to the Leyden battery, combined with a spark length, which it would otherwise have lost. (This property of long spark in the "cascade" arrangement of jars is well known.) If such an apparatus as here described be connected with the secondary poles of an induction coil, and other wires are then led off (with a break in the circuit, however, of to inches) to some piece of apparatus for the illustration of electric discharge in vacuo, such as Gassiot's cascade (especially with a canary goblet), the aurora tube, an electric egg of canary glass, &c. (but not a Giessler tube), the brightness of the illumination and volume of the discharge will be immensely increased. Thus a goblet invisible at 30 feet, when the unaided coil is used, becomes brilliant at 50 feet with this attachment. The author has used two coils with the above apparatus, both made by Mr. E. S. Ritchie, of Boston, one yielding a spark of 8 inches, the other, which gives, in its present mounting, sparks of 16 inches, to provide against accident; such a length being abundantly sufficient for use. Geissler tubes, unless of very large area, are not benefited in appearance by this arrangement, because the unaided coil can supply all the electricity they are capable of transmitting, and this excessive charge only tends to develop inductive resistances in the glass tubes themselves, which resistances this momentary current is the least fitted to overcome.

-ANIMAL PHYSIOLOGY AND
MORPHOLOGY.

PHYSIOLOGY.

...w phase of this question has been brought yable experiments of Dr. Parkes (of the lical School at Netley) on the Elimination an account of which he has communicated We have in a previous Chronicle noticed the of Fick, Wislicenus, Frankland, and the first earches. Dr. Parkes has found that during in excretes less nitrogen than during a period feeds on nitrogenous food or carbonaceous only. fter nitrogenous food has been cut off from the upplied, there is a retention of that nitrogen -needed to fill up some waste; also, that during or exercise, where nitrogenous food had not been cut increase in the elimination of nitrogen. The exuch these statements are founded may be thoroughly to important considerations, Dr. Parkes having iwo soldiers, and having every means of analysis be seen that they place the question in quite a new theory of the relation of food, muscle, and work can fle which does not account for them. Dr. Parkes' view voluntary muscle is brought into action by the inill, it appropriates nitrogenous matter and grows; the act of union gives rise to changes in the nonistances surrounding the ultimate elements of the bstance, which cause the conversion of heat into motion. tion continues until the effete products of these changes they have been shown to do by Ranke and others), a stensues, during which time the effete products are remuscle loses nitrogen, and can again be called into action uus. Dr. Parkes does not believe in the efficiency of ous foods when alone, which recent experiments might seem

Fick and Wislicenus, he says, drew upon the store of us matter in their system when they cut it off in their food, tains that carbon foods can only be efficient in the pretrogenous matter also. When a muscle loses nitrogen, fat l; formed, and thus a muscle, disintegrating during the frest, may form a store of fat in its texture, which may efficient at the next addition of nitrogenous matter as a of force. The argument as to the oxidation of nitrogenous being insufficient to account for work is true enough, but

See also Dr. Hinton's paper in the July number.

The author mentions another little practical detail in this connection. It is generally assumed that the induction-coil is unfit for the exhibition of those experiments of attraction and repulsion which especially characterize statical electricity. A great number, however, may be very satisfactorily exhibited by charging Leyden jars, and using them as the sources of electricity. Thus:-Connect a chime of bells with the knob of a large jar; connect the outer coating with the earth and with the negative pole of the coil; then bring the positive pole within striking distance of the knob, and charge by a few sparks. The electrical flyer, orrery, sportsmen, and birds may be successfully operated in this way, even in summer weather. The coil should not be of less than six inches spark length.

M. J. E. Balsamo has presented a memoir to the Academy of Sciences on a new Voltaic Pile. It is formed of two plates of iron, one plunged in dilute sulphuric acid, the other in a solution of chloride of sodium, separated from the acidulated water by a porous diaphragm. The iron of the acidulated water acts as zinc, and that of the saline solution acts as copper. The current, constant and of considerable intensity, proceeds from the property possessed by iron of polarizing itself differently in certain solutions, between which osmogenic action takes place. M. Balsamo has also tried another experiment of considerable theoretical interest. He plunges at the same time in oxalic acid two small magnetized bars of the same surface and of the same weight, one having its north pole in the liquid and its south pole out of it. The second bar is in the contrary position. The first acted as zinc, the latter as copper, and a current of electricity was the consequence.

M. Becquerel, sen., has continued his electro-capillary researches to which we drew attention in our last Chronicles. He shows definitely that-1. The alteration is exerted on the sides of the capillary spaces between two liquids. 2. The electricity is disengaged at the contact of these liquids in the capillary spaces. He has modified his method of experimenting. Instead of forming the fissures in the tubes, he fastens at their extremity a strong stopper very tightly fixed, made with filtering paper soaked in water; a platinum wire traverses the stopper and connects the two liquids together.

M. Bouchotte has examined the electrolytic power of the currents of the magneto-electric machine made by the Alliance Company. When the current sent by the commutator is always in the same direction, the electro-motive power is that of 144 Daniel elements with sulphate of copper; but when the current is alternate, as in the production of the electric light, the electro motive power is nil,