634 Of ^-^^ Excellent Qualities of Coffee. 



and even those particles which becoming thoroughly 

 soaked with the water are mixed with it, as they are 

 surrounded not by pure water, but by a solution of 

 coffee more or less saturated, that circumstance is 

 unfavourable to their solution. 



It is well known to chemists that any solid sub- 

 stance which is soluble in any liquid menstruum is 

 dissolved with greater difficulty or more slowly as the 

 liquid is more charged with that substance. 



Now, when coffee is made in the most advantageous 

 manner, the ground coffee is pressed down in a cylin- 

 drical vessel which has its bottom pierced with many 

 small holes so as to form a strainer, and a proper 

 quantity of boiling hot water being poured cautiously 

 on this layer of coffee in powder the water penetrates 

 it by degrees, and after a certain time begins to filter 

 through it. 



This gradual percolation brings continually a succes- 

 sion of fresh particles of pure water into contact with 

 the ground coffee, and when the last portion of the 

 water has passed through it every thing capable of 

 being dissolved by the water will be found to be so 

 completely washed out of it that what remains will be 

 of no kind of value. 



It is however necessary to the complete success of 

 this operation that the coffee should be ground to a 

 powder sufficiently fine, as has already been observed. 



This method of making coffee, by percolation, has 

 been practised many years, and its usefulness is now 

 universally acknowledged. I do not know who was 

 the first to propose it, but being thoroughly persuaded 

 of the merit of the contrivance I have been desirous 

 of recommending it; and I conceived that the most 



