[ « 3 
prevented from returning back upon the Fall of the 
Wind; and the Machine gives the Force of the 
higheft Blaft, lince the laft Time of Examination, 
without the Trouble of watching it. 
I have carefully examined the Dependence that 
may be had upon this Machine, during the late Storms 
in February 174I, by comparing the Height to which 
the Wind then forced the Velum, with the c Deal Let- 
ter. The 19th of Feb. Sabbath , 8 a. m . the Anemo- 
feope was at 75 : The Deal Letter for that Day called 
it a Storm. The Saturday following, being the 25 th, 
at 8 p. m. the Machine was at 79 : The 'Deal Letter 
called that a violent Storm. The Wednefday follow- 
ing, the laft of Feb. it was at 84: The Deal Letter 
called that a violent Storm. So that it appears, that, 
in fuch as the Sailors allow to be ’violent Storms , 
the Machine has hitherto anfwer’d well, and has had 
fix Degrees to fpare for a more violent Guft, before 
it comes to an horizontal Pofition. 
It is certainly to be depended upon in ordinary 
Weather, the Velum being hung fo tender, as to feel 
the gentleft Breeze. But, after all, I muft freely 
own, that I fear the expofing this Machine to all 
Winds, for a Continuance, muft foon diforder it ; and 
that irregular Blafts and Squalls cannot fail in a ftiort 
time to impair it. It may not therefore be amifs, to 
prevent this, for Gentlemen to take the Machine in 
in violent Weather ; and, by taking the Tube off the 
iron Axis, to make their Obfervations with the Tube-, 
Vane , and Velum , in their Hands ; which, as it is 
very light, and far from cumberfome, is eafy to do, 
as I have often experienced. 
B 2 
SECT. 
