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V. 



On the Aneroid Barometer. By Lieut. Kay, K.N., 

 F.R.S., Director of the Royal Observatory, Hobart 

 Toivn. [Read llth July, 1849.] 



This elegant little pliilosopliical instrument is of very 

 modern invention, having been first introduced to public 

 notice at a meeting of the British Association, held at 

 Swansea, in September, 1848. It may fairly be considered 

 a matter of congratulation to find that one has so soon 

 reached these shores ; and as the proprietor. Dr. Kenworthy, 

 has been so good as to entrust it to my care, with a request 

 that I would make any practical experiments w^hich I might 

 consider necessary for testing its powers, I have deemed it of 

 sufficient importance to bring the results before the notice of 

 the Eoyal Society of Tasmania. Its portability and accuracy 

 in denoting the changes in atmospheric pressure under 

 ordinary limits, and the ajoparent simplicity of the principle 

 on which it is constructed, appear to render it peculiarly 

 applicable to the wants of those persons who may desire 

 to possess a convenient house or marine barometer at a 

 moderate cost, without being liable to the derangement in 

 transit, which is so peculiarly the objection to the mercurial 

 barometer : on this account it will prove valuable to the 

 surveyor, the traveller, and perhaps also to the man of 

 scientific observation. Before proceeding to relate the 

 results of such experiments as I have been enabled to make, 

 it may be desirable to glance slightly at the principles on 

 which it is constructed, as far as I have been able to gather 



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