608 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



By the foregoing description it is seen, that the condensing water is 

 applied to the surface condenser, in the usual manner of a jet condenser, 

 viz.: as spray or a shower; I consider this the preferable mode to apply 

 the same, as thus the feature of an alternative, becomes operating, being 

 always ready to come into play as occasion shall require. Other varia- 

 tions in the construction may be made, whereby the jet must be especially 

 applied, as in the case of filling the tank and immersing the tubes, or 

 when the cold water is passed through the tubes. In the last named case, 

 the steam will be exhausted directly into the box, h, and the jet will only 

 be applied in case of accident — several of these modifications will here- 

 after be described. 



When Mr, Maynard resumed his seat, it was decided by the Association 

 to continue the discussion of Surface Steam Condensers at their next 

 meeting. Adjourned. ^^^^ 



American Institute Polytechnic Association, ) 

 March 11th, 1864. \ 



Chairman, Prof S. D. Tillman; Secretary, Mr. B. Garvey. 



New Barometer. 



During the time devoted to new inventions, Mr. G. Bartlett illustrated on 

 the black-board and described a newly invented barometer, which is form- 

 ed of a thermometer tube open'at the upper end, with a drop of mercury 

 near the middle, the space below being filled with air. At the time of ma- 

 king an observation the bulb is placed in the observer's mouth, to bring 

 the air of the bulb to the constant temperature of the body, when the height 

 of the mercury will indicate the weight of the atmospheric column. Quite 

 an animated discussion arose as to the feasibility of bringing the tempera- 

 ture of the instrument to the same point by the proposed method, in which 

 Messrs, Stetson, Bartlett, Maynard, Minthorne, Root, Dr. Parmelee, and 

 the secretary Mr. Garvey, participated. The prevailing opinion appeared 

 to be that for observations where strict accuracy was not required, the in- 

 strument would be convenient and useful. 



The Chairman read the following summary of scientific intelligence: 



Magnetic Storms. 



Mr. Airy, the Astronomer Roj^al of the Greenwich Observatory, in a pa- 

 per read before the Royal Society, propounds a theory to account for mag- 

 netic storms. The phenomena represent the movements of a magnetic 

 ether, which he supposes to overspread the whole surface of the earth, aa 

 an impalpable fluid envelope, several feet in thickness. If we conceive 

 this magnetic ether to be subject to occasional currents, produced by some 

 action or cessation of action of the sun, which currents are liable to inter- 

 ruptions and perversions of the same kind as those of air and water, we 

 have a theory by which the disturbances that occur in terrestrial magne- 

 tism may be explained. 



The Chairman remarked that this hypothesis may assist the student in 

 comprehending the action of extraordinary magnetic perturbations. It 



