202 M. Baumgartner on the Communication of Magnetism 



the atmosphere) the compressibility is in proportion to the 

 compressing powers. 



The compression produced by one atmosphere, as already 

 stated by Canton, is about forty-Jive millionth parts of the vo- 

 lume. Mr Perkins has obtained by a pressure of one hundred at- 

 mospheres, a compression equal to 0.01 (one hundreth of the vo- 

 lume) which is much more than could be expected from my 

 experiments. From calculations founded on the results of ex- 

 periments made with pressures beneath seventy atmospheres, 

 I have obtained only 0.0045 for 100 atmospheres. 



In consequence of this great discrepancy between my results, 

 and those of that highly distinguished inventor, I have repeat- 

 ed them with great care, and, from their simplicity, I believe 

 there is not much room to doubt of their accuracy. 



2. In so far as I have tried the temperature of compressed 

 water (to forty-eight atmospheres) no heat is liberated by its 

 compression. 



3. The compressibility of mercury is not much greater than 

 one-millionth of its volume by one atmosphere. 



4. The compressibility of sulphuric ether is nearly thrice 

 that of alcohol ; nearly twice that of sulphuret of carbon, but 

 only one and a third that of water. 



5. The compressibility of water containing salts, alkalies, or 

 acids, is less than that of pure water. 



6 The compressibility of glass is exceedingly small, and very 

 greatly beneath that of mercury. 

 Copenhagen, 

 December 30th 1826. 



Art. IV. — On the Communication of Magnetism to Steel, 

 by the direct white light of the Sim. * By M. A. Baum- 

 gartner, Professor of Natural Philosophy at Vienna. 



In repeating last summer the experiments of Mrs Somerville, 

 on magnetising wires by the influence of the coloured light of 

 the sun, I have discovered a process, which has succeeded 

 with more quickness and certainty than that of M. Morichini 



* Translated from the Ann, de Chim. November 1826, p. 333. 



