434 PHILOSOPHICAL TRANSACTIONS. [aNNO I76O. 



footed animals that feed only on vegetables. This dung is collected in the first 

 4 months of the year, when all their cattle, such as oxen, cows, buffiiloes, 

 camels, sheep, goats, horses, and asses, feed on fresh spring grass, which, in 

 Egypt, is a kind of trefoil, or clover; for when they are obliged to feed their 

 cattle on hay, and their camels on bruised date kernels, their excrements are not 

 fit for this purpose ; but when they feed on grass, the poor people of Egypt are 

 very careful to collect their dung quite fresh, and for that purpose follow the 

 cattle all day long, in order to collect it as it falls from them ; and if it is too 

 moist, they mix it with chaff, stubble, short straw, or dust, and make it up in 

 the form of cakes, about the same size and shape as it lies on the ground. Then 

 they fix it to a wall to dry, till it is fit to be burnt. 



For want of wood, which none but the rich in Egypt can afford to buy, they 

 burn this dung through the whole country, and sell a vast quantity of it to the 

 salt-makers. The excrements of the camel are not found at all preferable to any 

 other; and its urine is never used for this purpose, though generally reported so 

 by authors. The salt-workers pretend that the human excrements, and those 

 of goats and sheep, are preferable to any other. The months of March and 

 April is the only time they make the salt. 



Sal ammoniac is made in the following manner: They build an oblong oven, ' 

 about as long again as broad, of brick and moist dung, of such a size that the 

 outside, or flat part of the top of the arch, may hold 50 glass vessels, 10 in 

 Jength, and 5 in breadth, each vessel having a cavity left for it in the brick-work 

 of the arch. These glass vessels are globular, with a neck an inch long, and 2 

 inches wide. They are of different sizes, in different salt-works, con- 

 taining from a gallon to 2 gallons: but in general are about 18 inches dia- 

 meter. They coat each vessel over with a fine clay, which they find in the Nile, 

 and afterwards with straw ; they then fill them -|- full of soot, and put them into 

 their holes on the top of the oven. 



They make the fire gentle at first, and use the afore-mentioned dried dung for 

 the fuel ; they increase the heat gradually, till they bring it to the highest de- 

 gree, which the workmen call hell- fire, and continue it for 3 days and 3 nights 

 together. When the heat is come to its due degree, the smoke shows itself 

 with a sourish smell, that is not unpleasant; and in a little time the salt sticks to 

 the glasses, and covers the whole opening. The salt continues subliming, till 

 the above-mentioned time is expired ; then they break the glasses and take out 

 the salt, just in the same form, and of the same substance, that it is sent all over 

 Europe. At each salt-work they have a glass furnace to melt the old glasses, 

 and make new ones. 



