LIFE AND SCIENTIFIC LABORS OF STEFAXO MAEIANINL 181 



we must not fail to recall that by wliicli Mariauiiii obtains the sLock at 

 the opening of the circuit, although in the act of closing the circuit by 

 means of the finger or other unmoistened body, this shock be not ob- 

 tained. He subsequently occupied himself with the application of his 

 studies on electro-physiology to the cure of certain cases of paralysis, 

 and is, perhaps, the only physicist who has studied this subject with 

 suitable attention, and obtained by electricity the restoration in some 

 cases of those afflicted with this disorder. 



Among the numerous memoirs of Marianini, we must also cite as 

 worthy of remembrance and full of ingenious experiments, those with 

 which he sought to sustain the theory of the electro-motive force of 

 Yolta and to combat the chemical theory of the pile. Although it be 

 scarcely necessary to say that at present the latter theory is with reason 

 generally embraced, there are, nevertheless, some experiments of Maria- 

 nini which show that there are certain cases in which distinct signs 

 liresent themselves of the electro motive force as understood by Volta, 

 without the appearance of any phenomena of chemical action to which 

 those signs might be attributed. 



It remains, finally, to cite a long series of memoirs in which our col- 

 league studied the magnetizing force of the electric discharge of the 

 Leyden jar, as well as the inductive discharges. For the prosecution 

 of these exi)eriments, Marianini commenced by inventing a re-electro- 

 mcter, as he called it, which even now might be of service in many 

 researches, and which consists of an iron wire surrounded by one of 

 copper winding spirally about it, and placed above a compass in a direc- 

 tion perpendicular to the magnetized needle. A discharge from the jar, 

 however weak, now passes by the spiral and magnetizes the iron wire, 

 and the needle of the compass is deflected ; the direction of the deviation 

 indicating th€\ direction of the discharge. In this memoir a great number 

 of experiments' are described, by which it is proved that, after the mag- 

 netization generated by an instantaneous discharge, if the magnetization 

 be annulled either by mechanical means or by contrary discharges, the 

 iron acquires a susceptibility of being magnetized in the first direction, 

 and loses the susceptibility of being magnetized in the opposite direc- 

 tion. The author has studied with much sagacity all the other condi- 

 tions of this phenomenon, namely, the thickness of the iron wires, 

 the capacity of the Leyden jar from which the discharge is obtained, 

 and com])ares the eifects of a bundle of fine iron wires Avith those of a 

 large and full cylindrical wire. 



In continuation of these studies, Marianini proceeded to experiment 

 on the eft'ects produced by metallic envelopes in diminishing the mag- 

 netizing action of electric currents on the iron placed in the interior of 

 those envelopes, and demonstrated that the effects depend on the action 

 of the inductive discharge developed in the envelopes. He proceeded 

 afterwards to the study of inductive discharges ; discovered the induc- 

 tions of the second and third order, which had been found at the same 

 time by Henry, in America, and saw that the Leydeu-electric induction 

 was exerted also between liquid conductors. 



These notices, by which we have certainl3' had no thought of render- 

 ing justice to the various labors of Marianini, will serve at least to show 

 how assiduous and productive was the scientific life of our lamented 

 colleague, and how admirable an example that life, prolonged as it for- 

 tunately was, offers, in its unobtrusive and tranquil course, to the youth 

 ^f Italy — how imperishable an honor it will always reflect upon our 

 country. 



Floke>'CE, April 1, 18G7. 



