WRITINGS OF JAMES SMITHSON. 87 



found in gold or silver by fusing the slightest scrapings of 

 them with a little lead, &c., &c. 



Cut into very small, very acute triangles, clay affords a 

 flubstitute for Saussure's sappare. 



AN IMPROVED METHOD OF MAKING COFFEE. 



From Thomson's Annals of Philosophy, Vol. XXII ; New Series, Vol. 

 VI, 1823, page 30. 



June 4, 1823. 



Sir : From the highly fugacious nature of that part of 

 coffee on which its fine flavour depends, a practice has become 

 very generally adopted of late years of preparing the liquor 

 by mere percolation. 



This method has not only the great defect of being ex- 

 cessively wasteful, but the coffee is likewise apt to be cold. 



Coction and the preservation of the fragrant matter are, 

 however, not inconsistent. The union of these advantages 

 is attainable by performing the operation in a close vessel. 

 To obviate the production of vapour, by which the vessel 

 would be ruptured, the boiling temperature must be obtained 

 in a water-bath. 



In my experiments I made use of a glass phial closed 

 with a cork, at first left loose to allow the exit of the air. 

 Cold water was put to the coffee. 



This process is equally applicable to tea. 



Perhaps it may also be employed advantageously in the 

 boiling of hops, during which, I understand, that a material 

 portion of their aroma is dissipated ; as likewise possibly 

 for making certain medical decoctions. 



This way of preparing coffee and tea presents various ad- 

 vantages. It is productive of a very considerable economy, 

 since by allowing of any continuance of the coction without 

 the least injury to the goodness, all the soluble matter may 



