220 Intelligence and Miscellaneous Articles. 



for the induction are formed of flat spirals, of which the wires are 

 perfectly insulated. I stopped at the induced current of the fourth 

 order, as I only had three pairs of spirals. 



The induced currents of all the orders decompose water and 

 furnish detonating mixtures at each pole. The galvanometer re- 

 mains stationary. The re-electrometer of Marianini undergoes 

 continual perturbations in consequence of successive magnetizations 

 and demagnetizations. 



By producing a spark in the circuit, either by means of an electro- 

 micrometer or of the electrical egg partiallj' deprived of air, water 

 undergoes a polar decomposition ; the galvanometer acquires a 

 permanent deviation, the re -electrometer receives a fixed magneti- 

 zation, and these three pieces of apparatus always act concordantly, 

 whatever be the direction of the primary current, which may be 

 changed at pleasure by the commutator of Ruhmkorff's apparatus. 



The induced currents might be extended far beyond the fourth 

 order, and made to produce a continual series of sparks. 



The re-electrometer, the indications of which have always appeared 

 to me to be perfectly certain in the numerous experiments in which 

 I have used it, was employed to find the direction of the currents 

 induced by discharges of batteries charged by an ordinary electrical 

 machine, taking care that the spark of the induced circuit was at 

 the maximum striking distance ; the ingenious instrument of M. 

 Marianini leaves no uncertainty, and all the currents of diflferent 

 orders produced by strong discharges showed the directions which 

 had previously been found for weaker currents. — Comptes Rendus, 

 Dec. 15, 1S56, p. 1115. 



OBSERVATIONS ON THE ZODIACAL LIGHT AND ON SHOOTING 

 STARS. BY PROF. HEISS*. 



At the recent Meeting of German Naturalists at Vienna, Prof. 

 Heiss of Mvinster (Westphalia) gave the results of his observations on 

 zodiacal light (with reference to Prof. Argelander's memoir on the 

 same subject). 



The first notice of zodiacal light was published, about 200 j'cars 

 ago, by Dominic Cassini ; a more exact investigation has been un- 

 dertaken in recent times by Baron von Humboldt. The jihsenomenon 

 is generally difficult to observe on account of its want of conspicu- 

 ousness ; at certain periods, however, as was the case in the spring 

 of 1856, it becomes more intense, somewhat resembling a distant fire. 



Most authors state that the zodiacal light is visible only during 

 certain periods of the year ; Prof. Heiss, liuwever, after 200 observa- 

 tions, has found that it is visible during the whole course of the year. 

 In summer the protracted twilight is an obstacle to the observation, 

 but the presence of the zodiacal light maj'^ be precisely inferred from 

 the form of the crepuscular light. The determination of the limits 

 of zodiacal light requires particular care : the lower southern margin 

 of the pyramid is generally the less distinct. 



Prof. Heiss exhibited a map showing the shape of this light, as 

 * Communicated bv the Count Marschall. 



