Chronometers. — Obittia ry. 157 



fluids under equal circumstances move witli equal speed, in- 

 dependent of their specific weight, and that their motion is 

 merely determined by the pressure which acts upon them. 



CHROXOMETERS. 



It is only within these few years that a due value has been 

 attached to the aids to be obtained from good chronometers 

 in ascertaining the longitude at sea. It is but justice how- 

 ever to say, that since its value was duly appreciated, much 

 attention has been paid to this branch of science, especially by 

 our Board of Admiralty. It is pleasing to be able to state, 

 that they have employed active measures to manifest the value 

 which they attach to this object. To this Board the world is 

 indebted tor the eminently valuable labours of Dr. Tiarks, the 

 same gentleman who was employed to settle the boundary line 

 between the United States and the British possessions in North 

 America, who during the intervals of that service was sent with 

 the Owen Glendower frigate to Madeira, with about a dozen of 

 chronometers furnished by different makers of eminence, with 

 an understanding that those chronometers which are found to 

 perform best, will be purchased by the Board of Admiralty at 

 prices proportioned to their various merits. We know no 

 way in which a portion of the public expenditure can be more 

 beneficially applied. 



OBITUARY.— Mr. James Dickson. 

 On the 14th instant died at his house near Ci'oydon, aged 

 64, Mr. James Dickson, of Covent Garden, Fellow of the 

 Lintiaean Society, and Vice-President of the Horticultural So^ 

 ciety of London. — We shall be happy to be enabled in a future 

 number to give some account of this eminent and venerable 

 man. In the mean time, the following extract from the Life 

 of his brother-in-law, the celebrated Mungo Park, prefixed to 

 his Journal ( Ed. 1815) by the judiciousEditor, may be acceptable 

 to our readers. " Mr. Dickson was born of humble parents, 

 and came early in life from Scotland, his native country, to 

 London. For some time he worked as a gardener in the 

 grounds of a considerable nurseryman at Hammersmith, 

 where he was occasionally seen by Sir Joseph Banks, who 

 took notice of him as an ijitelligent young man. Quitting this 

 situation, he lived for some years as gardener in several consi- 

 derable families : after which he established himself in London 

 as a seedsman; and has ever since followed that business witli 

 unremitting diligence and success. Having an ardent passion 

 for botany, which he had always cultivated according to the 

 best of his means and opjiortunitics, lie lost no tune in pre- 

 senting 



