C 87 ] 
of : If to thefe we add Clujius , we have all that we 
are to expect of Certainty, amongft thofe who have 
mention'd it they being Eye-witneffes of what they 
wrote: Yet the Defcriptions of thefe are either fo 
imperfedt or unknown, that a very late Writer upon 
the Materia Medica ( a ), either not having feen or 
underhood them, has fallen into a Miftake about the 
Manna Arab urn, and his Authority may perhaps 
miflead others. 
My worthy Friend Peter Collinfon y having pro- 
cur'd a Sort of Manna from a Gentleman at Peters- 
burgh,u.nfet the Title of Manna Perficum ex plant a 
Al-Hagi Maurorum y was pleas'd to favour me with a 
Specimen of it : Iconfulted the principal Writers on 
the Materia Medica 5 and, finding their Opinions to be 
frequently oppoiite, and their Accounts in general 
perplexed, I imagined it would not be unacceptable 
to the Curious, to have fuch a Defcription of this 
Species, as would probably make it clear, that we 
have one Kind of the Manna Arabum hill extant, 
•viz. the Terniabin , and prevent any future Miftakes 
about it. 
The Specimen of Manna that now lies before me, 
appears, at firft Sight, to be a dirty reddifh brown co- 
lour'd mixed Mafs j which, upon a nearer View, is 
found to confift of, 
1. A great Number of globular, cryftalline, almoft 
pellucid Bodies, of a yellowifli -white Colour, and 
different Sizes ; the biggeft not much exceeding 
* Geoffroy Trail at. de Mat. Med. Vol. II. p. 5 86, &c. 
a large 
