There is no doubt as to the part played by electricity in the chemical effects of electro-metallurgy, but it will not prove useless for our subject to remark that when, in this operation, the current has become too weak, the deposit of metal, instead of forming in a thin, adherent, and uniform layer, sometimes occurs under the form of protuberances and crystalline, brittle nodules. When, on the contrary, the current is very strong, the deposit is pulverulent, that is, in a confused crystallization or in an amorphous state. Further along, we shall find an application of this remark. We obtain, moreover, all the intermediate effects of cohesion, form, and color of galvanic deposits. When, into a solution of acetate of lead, we pass a current through two platinum electrodes, we observe the formation, at the negative pole, of numerous arborizations of metallic lead that grow under the observer's eye (Fig. 1). The phenomenon is of a most interesting character when, by means of solar or electric light, we project these brilliant vegetations on a screen. One might believe that he was witness of the rapid growth of a plant (Fig. 2). The same phenomenon occurs none the less brilliantly with a solution of nitrate of silver. A large number of saline solutions are adapted to these decompositions, in which the metal is laid bare under a crystalline form. Further along we shall see another means of producing analogous ramifications, without the direct use of the electric current.--_C. Decharme, in La Lumiere Electrique._ * * * * * ELECTRIC TIME. By M. LIPPMANN. The unit of time universally adopted, the second, undergoes only very slow secular variations, and can be determined with a precision and an ease which compel its employment. Still it is true that the second is an arbitrary and a variable unit--arbitrary, in as far as it has no relation with the properties of matter, with physical constants; variable, since the duration of the diurnal movement undergoes causes of secular perturbation, some of which, such as the friction of the tides, are not as yet calculable. We may ask if it is possible to define an absolutely invariable unit of time; it would be desirable to determine with sufficient precision, if only once in a century, the relation of the second to such a unit, so that we might verify the variations of the second indirectly and independently of any astronomical hypothesis.