PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 55t 



Dr. Knight.— It will not. 



Mr. Garvey said he saw nothing very wonderful in it. It was 

 only a refined form of Roman cement. Oxydes have been used 

 by the Greeks and Romans. Artificial marbles have failed on 

 account of the mode of working them. Marbleized iron has a 

 preference over this material. Marbleized surfaces have been 

 put on slates, and have produced some very pretty patterns. 



Dr. Van der Weyde made some further remarks in reference to 

 telegraphing. He stated that magnets never lose their power, 

 and to prove which statement he produced two magnets, one of 

 which he said was twenty years old, and another one, a natural 

 magnet, that had belonged to his grandfather, which was a hun- 

 dred years old, both of which on being tested proved that they 

 retained their magnetic power. He also stated that if a piece of 

 soft iron or other material be attached to a magnet the magnet 

 will lose its power, and the iron will fall to the ground. 



Adjourned until Thursday evening, January 24, 1861. Subject, 

 " Projectiles for rifles and rifled cannons." 



American Institute, Polytechnic Association, ) 

 January 24, 1861. ] 



Prof. Mason in the chair. 



Mr. John Brown proposed the subject of " Fuel " for future 

 consideration. 



Mr. Garvey proposed the subject of the "Theory of language." 



Dr. Van der Weyde presented a new pyrometer, which he 

 stated could be used as a pressure gauge. He exhibited another 

 apparatus which showed the connexion between pressure and 

 temperature. Temperature, he stated, could not be raised with- 

 out raising the pressure. He also exhibited the following table 

 of temperatures, prepared by himself: 



TABLE OF TEMPERATURES, by P. H. Van der Weyde, M. D. 



Scales. 



Particulars concerning each Temperature. 



Formerly sup- ") Cerium, chromium, titanium, tungsten, 

 posed by some [Platinum, uranium, osmium> iridium, 

 to be the melt- f Molybdenum. [nickel, 



ing point of: j Palladium, manganese, bar-iron, cobalt, 



[These results of old investigations made with Wedgewood's 

 pyrometer (and reduced by taking each dcg. of this instru- 

 ment = 75° C. about) are still copied by many authors, 

 notwithstanding they are evidently much too high, like all 

 old observations above 300° C] [the centre of the sun. 



The highest temperature we can conceive of, exists probably at 



