Of the Excellent Qualities of Coffee. 649 



When the boiler is filled with boiling water, both 

 covers must be removed ; but the small cover only is 

 removed when the ground coffee is put into the strainer, 

 and when boiling water (which may be drawn out of 

 the boiler) is poured on it. 



The reservoir for the coffee is firmly fixed in its 

 place in the middle of the boiler, by means of three 

 short feet of strong tin (of about half an inch in height), 

 which are soldered to the reservoir and to the boiler. 



The form of the reservoir is conical ; and it is about 

 6 inches in diameter below, 4^1,- inches in diameter 

 above, and 7^ inches in height. 



By using two or three strainers successively, sixteen 

 or eighteen cups of coffee may be made in this urn ; 

 and when the strainers are taken away, and the reservoir 

 is quite filled with coffee, it will hold more than twenty 

 cups. 



This urn has been found to be very useful for serv- 

 ing up coffee after dinner to large companies ; and it 

 is the more so, as those who find their coffee too strong 

 can easily make it weaker by mixing with it a little 

 boiling water, which may be drawn from the boiler 

 which is always at hand. 



The form of the boiler and that of its large cylin- 

 drical strainer are faintly represented in the figure 

 by dotted lines. 



The boiler must always be filled with water already 

 boiling hot ; for the lamp, though quite powerful enough 

 to keep this water boiling hot, and even to make it boil 

 with violence, does not furnish heat enough to heat 

 so great a quantity of cold water, and make it boil- 

 ing hot in any reasonable time. 



As often as the smallest quantity of steam is seen to 



