600 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



Charybdis, and thence passes westward through the interior of the 

 earth, becoming heated by volcanic fires, and charged with the sul- 

 phate of copper, until it finds vent in a vast chasm along the 

 American shore. The water of the Gulf Stream is in perpetual 

 eddies, as though boiling up from below. The animalcule of the 

 Gulf Stream are not found in the Gulf of Mexico or the Bay of 

 Campeachy, but are identical with those found in the Mediterra- 

 nean sea. The sedges found in the Gulf Stream are identical 

 with the fuci of Egypt, and are probably derived from the Nile. 

 The odor and taste, derived from the sulphate of copper, are 

 found only in our Gulf Stream, and in similar streams. The 

 reason of the failure of the Atlantic Telegraph was probably, 

 that there is a deep chasm opposite the coast of Ireland, the 

 bottom of which no cable could reach. The geysers of Iceland 

 rise and fall with the tides, indicating a connection with the 

 ocean, while warmed by volcanic fires. 



THE PYROMETER. 



Dr. Vander Weyde exhibited a pyrometer invented by Mr. G. 

 C. Aycrigg, sixteen years ago, and another of Gauntlet's patent, 

 sent from England, similar to his own in general principle, ex- 

 cepting that the different metals extended the whole length of 

 the handle instead of being confined to one end. These pyro- 

 meters being exposed to a certain heat, the longer the exposure 

 the greater would be the temperatures indicated, because a greater 

 length of the two metals would be heated. But Van der Weyde's 

 pyrometer, having the tube and the enclosed rod of the same ma- 

 terial, excepting for a few inches at the end, the conduction of 

 heat up the handle would not affect the results shown by the 

 index. 



Mr. Seely. — Unless the pyrometer was to be employed for 

 specific purposes, I should not think it of much value. For high 

 temperatures, Wedgewood's pyrometer may be used ; and for low 

 temperatures, the mercurial thermometer is the best. For sci- 

 entific purposes, there are other methods of measuring heat more 

 accurate than any pyrometer. Oxygen diluted with nitrogen, 

 will produce in the combustion of hydrogen, a certain degree of 

 heat which can be measured with a mercurial thermometer. Put 

 in less nitrogen, and the temperature will be higher, but can still 

 be measured. Thus we have a scale that determines with accu- 

 racy, the difierent degrees of temperature. Make the mixtures 



