186 Scientyic Intelligence, — Meteorology. 



could therefore no longer be relied on. The circumstances at- 

 tending the accident which is the subject of this paper, are con- 

 sidered by the author as strongly confirming the value of 

 conductors to ships in obviating the destructive effects of light- 

 ning. From the inquiries he has made, he is led to the belief, 

 that injuries from lightning at sea are much more frequent than 

 is generally imagined. One source of increased danger of late 

 years, is to be found in the greater proportion of metal, and par- 

 ticularly iron, which is employed in the rigging ; more espe- 

 cially as the metallic masses are there nearly insulated, or con- 

 nected only by very imperfect conductors. In the instance be- 

 fore us, it is in the highest degree probable, that if the New 

 York had been without the protection of the conductor, she 

 must inevitably have been destroyed by the second tremendous 

 explosion, which, thus guarded, she sustained without the slight- 

 est injury. The author remarks, that copper is a better mate- 

 rial for such a conductor than iron, from its being less liable 

 either to fusion or corrosion ; and also that a rod is, from its 

 continuity, a better form of conductor than a chain. In the 

 case of ships, however, the greater convenience of a chain, aris- 

 ing from its flexibility, will generally ensure it the preference. 

 The author recommends that, instead of carrying the conduc- 

 tor through the decks to the keels^ as suggested by Mr Harris, 

 the lower end of the chain should be kept at a distance from 

 the sides of the ship, by means of a light out-rigger or spar, as 

 was done in the New York. 



3. O71 the Diurnal Course of the Thermometer. — 1. The 

 mean daily course of the temperature of the atmosphere is the 

 same at all hours, as is proved by the observations made by the 

 Officers of Artillery at Leith Fort, those of Chimenello in Pa- 

 dua, of Dr Neuber in Apinrade, and of B. S. Dorta at Rio de 

 Janeiro. 2. According to an yearly mean, the coldest hour of 

 the day in Europe is 5 o'clock in the morning. 3. The warmest 

 hour of the day, according to the Leith observations, is 3 o'clock 

 in the afternoon, but the Padua observations make it S o'clock 

 in the afternoon. 4. The progress of the heat is interrupted 

 near to the maximum and minimum : the rise is most conside- 

 rable some hours after the minimum, the fall some hours after 

 the maximum. 5. The heat increases for 9-10 hours, decreases 

 for 14-15 hours. 6. The greatest daily range of temperature 



