( 144^ ) 
This rifing and falling of the green Weeds may Teem ftrange 
to iome people, but it they will be convi^iced bythe Experi- 
ments of natural Philofophers whom I have followed fc ve- 
ra! years, let them take a fmall Glafs-bubble, fach as is de- 
fcrib'd by Fig lo. Q R. S T, leaving the fmali orifice at T 
open for the Water to run in and out ^ and let this Bubble 
be put into a V ^flel with Water, they will find in Summer 
that by the dilation of the Particles of Air within the faid 
Bobble, it will rife to the fuperfiejesof the Water, whereas 
the lame Air, ihro its elafticity, being contracted in cold 
Weather, will make room for the admiflion of* a Mafs of 
Water fo much heavier than itfeif into the faid Babble, and 
then it will fubfide 3 and this will happen totks qmtks. 
IV. A Letter from the ^VerendMr William Derham, 
F. R. S. to \fr John Haughton, F. R. S, contam-^ 
in^ his Ohferyatlons on the Weather^ See. for fome 
.years lafi fafi. 
Vpminfier^ Apyl the jth, 1703. 
'i Lately fen t my Weather and Tables of laft year to Dr 
J. Sloane^ and promised wheii I fliould hear from Mr Tomit- 
le/ in I ancapirey an Account of what he wujte that wasca- 
ripiis : , I have lately receiv^ d Mr Towmkys Lef ter, and take 
the-.QccafiQn of ; that Letter ^ riow to ycni, to give^ 
you?my hearty thanks for all fttvours that 1 have received 
from you 5 as well as to fend you fome. of that ingenious, 
curious Gentleman's Ob fervations of laft year, and my own. 
And firft, As tothe moft remarkable .Weather, icfpecially 
Rain, of laill year,. dafnd,, die. :e thereof : Mr Towntkj 
tdls nie^ tii^ is ^ (general ^iComi:>l»int in tlie.Nortb^f E>ng- 
