(3 9 ) 
V. A Defcription of a Barometer, wherein 
the Scale of Variation may he encreafed 
at <P leaf tire. !By the Reverend Mr. John 
Rowning, Fellow of Magdalen -College in 
Cambridge j Communicated hy T>r. Smith 
F. ^ 5. 
A BCD, in Fig. 4, is a Cylindrical Veflel fil- 
led with a Fluid to the Height W, in which 
is immerged the Barometer S V, confifting of the fol- 
lowing Parts ; the Principal of which is the Glafs 
Tube T P (reprefented Separately at t f) whofe 
upper End T is hermetically lealed ; This End does 
not appear to the Eye, being received by the lower 
End of a Tin Pipe G H, which in its other End G 
receives a Cylindrical Rod, or Tube S T, either 
hollow or iolid, made of any Materials whatfo- 
ever , thereby fixing it to the Tube T P. The Rod 
S T may be taken off^ in order to put in its ftead a 
larger or lefier, as Occafion requires. S is a Star at the 
Top of the Rod ST, which ierves as an Index, point- 
ing to the graduated Scale L A, which is fixed to 
the Cover of the Veflel ABCD. M N is a large 
Cylindrical Tube made of Tin (reprelented iepa- 
rately at m n) which receives in its Cavity the 
fmaller Part of the Tube TP, and is well cemen- 
ted to it at both Ends, that none of the Fluid can 
get in. 
The 
