478 



SCIENCE. 



with its 80,000 volts, and supply it by secondary 200-volt 

 dynamos or ioo-volt dynamos, through proper distributing 

 wires, to the houses and factories and shops where it is to 

 be used for electric lighting, and sewing machines, and 

 lathes, and lifts, or whatever other mechanism wants 

 driving power. Now the thing is to be done much more 

 economically, I hope, and certainly with much greater 

 simplicity and regularity, by keeping a Faure battery of 

 40,000 cells always being charged direct from the electric 

 main, and applying a methodical system of removing sets 

 of 50, and placing them on the town-supply circuits, while 

 other sets of 50 are being regularly introduced into the 

 great battery that is being charged, so as to keep its num- 

 ber always within 50 of the proper number, which would 

 be about 40,000 if the potential at the emitting end of the 

 main is 80,000 volts. 



ON THE ARRESTATION OF INFUSORIAL LIFE.* 



By Prof. Tyndall. 



Three years ago I brought with me to the Alps a 

 number of flasks charged with animal and vegetable in- 

 fusions. The flasks had been boiled from three to five 

 minutes in London, and hermetically sealed during ebul- 

 lition. Two years ago I had sent to me to Switzerland a 

 batch of similar flasks containing other infusions. On 

 my arrival here this year 120 of these flasks lay upon the 

 shelves in my little library. Though eminently putre- 

 scible, the animal and vegetable juices had remained as 

 sweet and clear as when they were prepared in London. 

 Still an expert taking up one of the flasks containing an 

 infusion of beef or mutton would infallibly pronounce it 

 to be charged with organisms. He would find it more 

 or less turbid throughout, with massive flocculi moving 

 heavily in the liquid. Exposure of the flask for a minute 

 or two to lukewarm water would cause both turbitity and 

 flocculi to disappear, and render the infusion as clear as 

 the purest distilled water. The turbidity and flocculi 

 are simply due to the coagulation of the liquid to a jelly. 

 This fact is some guarantee for the strength of the in- 

 fusions. I took advantage of the clear weather this year 

 to investigate the action of solar light on the development 

 of life in these infusions, being prompted thereto by the 

 interesting observations brought before the Royal Society 

 by Dr. Downs and Mr. Blunt, in 1877. The sealed ends 

 of the flasks being broken oft", they were infected in part 

 by the water of an adjacent brook, and in part by an in- 

 fusion well charged with organisms. Hung up in rows 

 upon a board, half the flasks of each row were securely 

 shaded from the sun, the other half being exposed to the 

 light. In some cases, moreover, flasks were placed in a 

 darkened room within the house, while their companions 

 were exposed in the sunshine outside. The clear result 

 of these experiments, of which a considerable number 

 were made, is that by some constituent or constuents of 

 the solar radiation an influence is exercised inimical to 

 the development of the lowest infusoria. Twenty-four 

 hours usually sufficed to cause the shaded flasks to pass 

 from clearness to turbidity, while thrice this time left the 

 exposed ones without sensible damage to their transpar- 

 ency. This result is not due to mere differences of tem- 

 perature between the infusions. On many occasions the 

 temperature of the exposed flasks was far more favorable 

 to the development of life than that of the shaded ones. 

 The energy which in the cases here referred to prevented 

 putrefaction was energy in the radiant form. In no case 

 have I found the flasks sterilized by insolation, for on re- 

 moving the exposed ones from the open air to a warm 

 kitchen they infallibly changed from cleaness to turbidity. 

 Four and twenty hours were in most cases sufficient to pro- 

 duce this change. Life is, therefore, prevented from devel- 

 oping itselt in the infusions as long as they are exposed to 

 the solar light, and the paralysis thus produced enables 



them to pass through the night time without alteration. 

 It is, however, a suspension, not a destruction, of the 

 germinal power, for, as before stated, when placed in a 

 warm room life was invariably developed. Had I had 

 the requisite materials I should like to have determined 

 by means of colored media, or otherwise, the particular 

 constituents of the solar radiation which are concerned 

 in this result. The rays, moreover, which thus interfere 

 with life must be absorbed by the liquid or by its germinal 

 matter. It would therefore be interesting to ascertain 

 whether, after transmission through a layer of any in- 

 fusion, the radiation still possessed the power of arresting 

 the development of life in the same infusion. It would 

 also be interesting to examine how far insolation may be 

 employed in the preservation of meat from putrefaction. 

 I would not be understood to say that it is impossible to 

 sterilize an infusion by insolation, but merely to indicate 

 that I have thus far noticed no case of the kind. 



PLANTE'S RHEOSTATIC MACHINE* 



Translated from the French by the Marchioness Clara Lanza. 



Ruhmkorff's electric induction machine has proved in 

 the most satisfactory manner that by the intermediary of 

 inductive action, we can transform voltaic electricity into 

 electricity of high tension. M. Bichat has likewise 

 shown that by the same means, currents of high tension 

 can be changed to currents of quantity, analogous to 

 voltaic currents. M. Plante, with his secondary piles, has 

 rendered this demonstration still more emphatic, and as 

 his experiments demanded a greater tension than he was 

 able to produce with his batteries, he undertook the man- 

 ufacture of an apparatus by which he could obtain ver- 

 itable discharges of static electricity, capable of forming 

 at will, long thread-like sparks, or short, thick ones. 

 In this way he was induced to make the battery of which 

 we are about to speak, and which he calls the rheostatic 

 machine. 



Although this apparatus (fig. 1) was presented to the 

 Academy of Sciences and exhibited to most of the phy- 

 sicians who witnessed M. Plante's fine experiments, it 

 is as yet, but little known. Why this should be the case 

 we are at a loss to understand, for it is one of the most 

 perfect machines that can be employed in experiments of 

 static electricity. Had the apparatus borne a foreign name, 

 we are confident it would have attracted considerable at- 

 tention long ago. It is much to be regretted that we are 

 so constituted in France, that whatever is invented by an 

 unknown man, a savant who does not rejoice in an es- 

 tablished position or who is not a member of some scien- 

 tific coterie originating from a celebrated school, is 

 looked upon entirely as a matter of subordinate interest. 

 " It is only an amateur's work," we hear on all sides for 

 awhile and then the subject is dropped forever. In Eng- 

 land it is quite different. Amateurs such as Grove, 

 Gassiot, Warren, Delarue, Spottiswoode, Lords, Ross, 

 Lindsay, Raleigh, Elphinstone and many others, find their 

 efforts are appreciated as they deserve to be, and no one 

 ever thinks of inquiring whether they are savants patented 

 by the government or not. 



M. Plante therefore, not being among the last-men- 

 tioned, was forced to meet with indifference which he 

 forcibly overcame later by the fine work he performed 

 with his accumulators. He was not so successful, un- 

 fortunately, with his rheostatic machine, and for this 

 reason we shall dwell a little upon the important results 

 it has afforded us. 



M. Plante's machine consists of a series of condensers 

 with mica plates, parallel one with the other and capable 

 of being charged and discharged in a manner similar to 

 his secondary batteries without any other alimentary 

 electric source than these latter. 



The various pieces composing the apparatus must be 



* British Association, 1881. 



* La Lumiire Electrigue, August 6th, 1881. 



