Mr. Castles’s Obfervations , &c. 34 y 
an Adt was paffed, by which fuch difeoverer was entitled to 
twenty thoufand pounds, to be paid from the public treafury of 
the ifland. 
Many were the candidates on this occafion, but very far 
were any of them from having any juft claim: neverthelefs, 
confiderable fums of money were granted, in confideration of 
trouble and expences in making experiments. 
In Grenada there had always been feveral fpecies of ants, 
differing in fize, colour, &c. which however were perfedtly 
innocent with refpedt to the fugar-cane. The ants in queftion, 
on the contrary, were not only highly injurious to it, but to 
feveral forts of trees, fuch as the lime, lemon, orange, &c. 
Thefe ants are of the middle fize, of a (lender make, of a 
dark red colour, and remarkable for the quicknefs of their 
motions ; but their greateft peculiarities were, their tafte when 
applied to the tongue, the immenfity of their number, and 
their choice of places for their nefts. 
All the other fpecies of ants in Grenada have a bitter mufky 
tafte. Thefe, on the contrary, are acid in the higheft degree, 
and, when a number of them were rubbed together between 
the palms of the hands, they emitted a ftrong vitriolic ful- 
phureous fmell ; fo much fo, that, when this experiment was 
made, a gentleman conceived, that it might be owing to this 
quality that thefe infedts were fo unfriendly to vegetation. This 
criterion to diftinguilh them was infallible, and known to every 
one. 
Their numbers were incredible. I have feen the roads 
coloured by them for miles together ; and fo crowded were they 
in many places, that the print of the horfes feet would appear 
for a moment or two, till filled up by the furrounding multi- 
tude. This is no exaggeration. All the other fpecies of ants, 
Z z z although 
