202 LETTER VIII. 



lours on the Back and a clear filver white on the 

 Belly. Their heads are of different Colours, fome 

 being all over filver. Their Fins are generally red, 

 and fometimes the Colour of their Heads. In fliort 

 they are extreamly beautiful. Mr. Margas fent 

 for a dozen of them by an Eaji-India Captain, 

 In China they were all red, except two ; But 

 when they came hither they changed into all 

 manner of Colours. They live in Thames Water y 

 and if the Bafon be filled with muddy Water, 

 they will purify and render it full as clear as 

 the fineft Pump Water in a quarter of an hour 

 or lefs. Sometimes he gives them a little piece 

 of Bread ; but he thinks they are better without 

 it, as having feveral die when he fed them, and 

 none when he did not. I am apt to imagine, that 

 they may eafily enough preferve Life, by fwal- 

 lowing the Mud, and fuch Animacula as are found 

 in all Waters, even in the very pureft. 



22. The word Tornado (or Tiirnado) in the 

 Marine Dialect, fignifies a fudden and moft violent 

 Storm of Wind (accompanied with dreadful Light- 

 nings) which ufually lafts for an hour, and is fuc- 

 ceeded by as fudden and ftill a Calm: Thefe 

 Storms are very common in hot fultry Climates 

 as far as the feventeenth Degree of Latitude on 

 both fides of the Equinodlials efpecially when the 

 Sun is at or near their Zenith. 



