( 349 ) 
A Letter written to the Fuhlifher by the 
Learned Mr. Ray, containing feme Con- 
fiderations on the ConjeBure Numbe 
114. of thefe Trails ^ about the fmim- 
ing Bladders in Fijhes. 
thu Letter u not mentioned, in the Contents ^ becaufe it V0<is 
thought at the t ime when the firfl jbeet vpas a printing, the 
Difiourfe about the precedent Infirument would have ta^ 
ken up all the room of this traB* 
SIR, 
I was much pleafed and facisfied with the ingenious conjefture 
I found in your Iranfailions of May laft, pag, 3 ro. concern- 
ing the fwimming Bladders of Fifties ; and perfwade my fe f 
that the Author thereof hath hit upon their true uTe , viz. to 
fuftain or keep them up in any depth of vvater. For i.it hath 
been obferved by fome, and I find it in Mn Willughbyes general 
notes of Fiflies, that if the fwimming bladder of any Fi(h be 
pricked or broken , fuch a Fifii fiqks prefently to the bottom , 
and can neither fupport nor raife up it felf in the water. 2. Flat 
Fifties, diS Soles ^ Flaife^&cc. which lie alwaies grovelingat the 
bottom, have no fwimming bladders that I could ever find. 
3. In moft Fifhes there is a manifeft channel leading from the 
gullet or upper orifice of the ftomach to the faid bladder,vvhic^ 
without doubt ferves for convey ing air thereinto ^ as may ea- 
fily be tried by any one that pleafes. But though air may be 
received into the bladder , yecis there a value or fome other 
contrivance to hinder the egrefs of ic^ for you fljall fooner 
break the bladder than force any air out by this channel. Yet 
in Sturgeons Mr. Willughby hath obferved ^ that prefling the 
bladder 
