( *9 ) 
Befides this method of deftroying infects, there is another, 
which, for the benefit of mankind, lhould be generally known, 
particularly as moft (hips that pafs through warm climates are in- 
felted with thofe difagreeable ones called cock-roaches. 
The following preparation will prevent them from fpoiling 
many valuable articles on the voyage, and perhaps be of ufe in 
having feeds, books, and papers, which they are apt to deftroy 
on board of fhips: at the fame time we fhall find that this prepa- 
ration is equally deftruftive to all other infedts. Diilblve one 
ounce of crude fal-ammoniac in a quart of water, then put in two 
onnces of corrofive fublimate mercury. This folution, when ufed, 
lhould be firft heated in the following manner: put the liquor into 
a phial, and fet it in a tin pot of water on the fire, and when the 
water boils, the folution in the phial will be heated enough. N. B. 
The phial with the folution mull be put into the water when it is 
cold, and then there will be no danger of breaking the phial: a 
piece of packthread or wire lhould be put round the neck of the 
phial, to lift it in and out of the water: it will corrode every velfel 
but glafs; therefore it is neceftary that it lhould be heated in the 
foregoing manner. You muft ufe a hog’s-briftle bru fh to walh 
over any box or furniture. 
It is Iikevvife tco well known, the great damage done to wheat by this pernicious infedl 
the weevil, which, after feeding on the infide of the grain, eats its way out : how it comes 
into the grain, is a confideration worthy of the attention of the philofopher. 
The farne obfervation may be made on turnip-feeds kept confined in facks in hot weather, 
where tire moift heat brings the animals to life. This affords us a very uieful hint in regard to 
the black fly, as it is called, that defrays the newly-fown turnips in dry weather, juft as their 
lobe leaves are expanded ; and points out to us the probability that this little animal, which 
afterwards deftroys the tender plant, may have exifted in the feed itfelf ; fo that it is a confide, 
ration well worth the farmer’s notice, to try either by fumigating his feed well with burnnig 
brimftone, or by foakingthem in brimftone and water, or by diftblving a fmall portion of liver 
of.fulphur in water, and fteeping his feed in it, to deftroy tliefe animals. If thefe experiments 
are made with judgement, there is great probability that we 11; all able to deftroy the animals 
without affefting the vegetation of the plant. 
D 2 
The 
