24 JAMAICA. 



fitted {late to reflet images; and to this effea the great height and 

 vicinity of the inclodng ridges very much contribute [/j]. It is 

 ftrange, indeed, that the experiment, tried upon it fo long ago by 

 Sir WiUiam Beefton, has not correded this popular error; for he 

 found, that with an infufion of galls the water acquired a deep 

 green inclining to black [/]. But the mofi: certain tefl: of an in- 

 termixture of copper is made with the cauftic volatile alkali , as fpirft 

 of Jal amtnon, combined with quick lime-water; thefe, if the 

 fmalleft particles of copper be dillbhed, would caufe the whole to 

 aflume a beautiful blue colour. This experiment was tried fome 

 years fince by Doftor Browne, without producing any fuch elJe£l. 

 Now, as the tefl of an iron impregnation is the black or duflcy co- 

 lour it ftrikes with the vegetable aftringents, fuch as tinfture of 

 galls, and as the fojjik alkali will give a greenifli cafl, it feems pro- 

 bable that this river is impregnated with no other metal than iron, 

 and with a copious admixture of a calcareous earth, or lime. 

 The purgative quality of the water, when drunk immediately from 

 the river, is very properly conjeclured by Dodor Browne to proceed 

 from the clay with which it is in general copioufly charged; be- 

 caufe it lofes this quality when fettled in jars and cleared of its 

 Joad ; which would not be the cafe if it proceeded from iaits, or a 

 folution of metals ; and becaufe many other waters, of fimilar ap- 

 pearance, poifefs the like qualities hi their turbid (late, though 

 known to be not impregnated with metallic fubflances. Agreeably 

 to this opinion, it is found by the inhabitants of the town, who 

 keep this water in large jars, that, after {landing for fome time till 

 the foeculencies have fubfided, it entirely lofes the effeft juft men- 

 tioned, and becomes as clear, foft, and plealant, in its depurated 

 flate, as any water in the world. In this ftate it was tried by an hy- 

 droflatical apparatus, and found equal in lightnefs to Briflol Hot- 

 well water. We may therefore fafely conclude, that it has been 

 very unjuftly fligmatized ; and that, if the Spaniards fuppofed it 

 impregnated with coppei', they adopted this miftaken notion 



[/'] So Virgil calls the river Tyber cxnileits, azure, or Iky-coloured. Mn. viii. v. 64. Some 



have conjectured, that the original name was Rio Cobra, trom the Portugtiefe coira, which fignifies 

 a fnake, and might with great propriety allude to the Terpentine courfe of this river. 



[?■] An infufion of galls in water, impregnated with copper and quick lime, (Iruck an orange 

 ^colour inclining to reddilh. 



through 





