256 NATURAL HISTORY. 
'I'I'.e elephant and rhinoceros, which, by 
reafon of their enormous bulk, and the va(t 
quantity of food and water they daily need, 
cannot ihift to defert and dry places, are 
obliged, in order to refid the zimb, to roll 
themfelves in mud and mire, which, when 
dry, coats them over like armour. • 
Of ail thofe who have written of thefe 
countries, the prophet Ifaiah alone has given 
an account of the zimb, or fly, and defcri- 
bed the mode of its operation. Ifaiah, chap, 
vii. ver. 18 and 19. Providence, from the 
beginning, it would appear, had fixed its ha- 
bitation to one fpecies of foil ; which is a 
black, fat jsarth, extremely fruitful. And, 
contemptible as it feems, this infeft has in- 
variably given law to the fettlement of the 
country : it prohibited, abfolutely, thofe in- 
habitants of the black earth, called Mazaga, 
houfed in cavbs and mountains, from enjoy- 
ing the help of labour of any beafts of bur- 
den. It deprived them of their flefli, and 
nnik, for food ; and gave rife to another 
nation, leading a wandering life, and pre- 
ferving immenfe herds, by conducing them 
into the fands, beyond the limits of the 
black earth, and bringing them back when 
the danger from this infeft was over. 
In the plagues brought on Pharaoh, it was 
by means of this infed that God laid he 
would feparate his people from the Egyp- 
tians. The land of Goflien, the pofleffion 
of the Ifraelites, was a land of pallure, not 
tilled, 
