Inundations. — Electricity. 



267 



This system has already worked for a month with entire regularity ; and 

 when it shall have been firmly established and have received the sanction 

 of time, M. Leverrier will undertake to extend the system to the neigh- 

 boring countries. The concurrence of Belgium is promised, and we hope 

 for that of England. Indeed, according to a recent statement at the Ob- 

 servatory, the brother of the Austrian emperor and the Royal Prince of 

 Sweden have promised to contribute all in their power to promote the ex- 

 tension both of the political union and meteorological union of France 

 to Austria and Sweden. But it is well known what such promises are 

 worth. 



Inundations. — Since the calamity from floods which has befallen a part 

 of France, many notes and memoirs have been published, both with ref- 

 erence to preventing such catastrophes in the future, and the discovery of 

 the cause. On the latter point there are two opinions, some attributing 

 the rain to hot vapors brought with the winds of Africa, others to the 

 Gulf stream descending very low in the ocean at this time and saturating 

 the air with moisture. Both theories consider the winds as carried against 

 the Alps, there to precipitate their moisture in the state of rain ; and it 

 is in accordance with this view that the part of Germany beyond the Alps 

 to the south and east has suffered from drought. 



To these meteorological causes, supposing one or both real, we may add 

 the clearing away of forests, the opening of canals, and the means used 

 to facilitate the flow of waters, whence, a drop of water makes a quicker 

 passage to the rivers and thence to the sea, than in tne ancient times of 

 uncultivated France. The rivers consequently enlarge suddenly beyond 

 measure and commit ravages from which France periodically suifers. It 

 seems the duty of science then to combat the evils due partly to the pro- 

 gress of science. The organization of a system of meteorological ob- 

 servations is one step towards this end. The inspection of the pluviome- 

 ter may enable us to foresee by several days the increase of a river, like 

 that at Lyons ; and if placed about the heights, the telegraph may an- 

 nounce six days in advance, a flood on the Saone, and enable the people 

 to put the rivers in a state to carry off the excess of water and prevent 

 much of the evil. MM. Pouillet, Regnault and others will hardly deny 

 after this the utility of meteorological observations. 



Electricity. — Substitute for the copper wire in the construction of He- 

 lices. — The cost of helices of fine wire, and the limit of thickness to which 

 the fine wire can be covered with silk for insulation, are two impedi- 

 ments which M. Bonelli has sought to set aside by very simple means. 

 He takes a band of paper of the height of the helix of an electro-mag- 

 net, or of the corresponding part of a galvanometer; this band carries 

 parallel to its edge, metallic lines a a\ b b', etc., passing from one extrem- 

 ity to the other ; these lines, placed in the circuit, will give passage to the 

 current, while they are also insulated from one another by the paper 

 which separates them ; so that the current will pass uninterruptedly 

 provided the lines of metal are unbroken. The number of these lines 

 which may be put on a band of paper is almost indefinite. Leaving 

 their extremities free, the current may be made to pass, either along 

 the lines united, or in all of them at the same time and iu the same 

 direction. 



