Meafuremeht of a Bafe on Ho u n do w-Hea th . 435' 
1 can be little dbubt, that deal rods will be univerfally- remedied by ■ 
other countries, in any mealurements they may have occafion 
« ; v * 
to make in future. 
About the 10th of July, two rods, one of New-England 1 
and the other of Riga deal, being meafured by the fixed points ‘ 
in the great plank in Mr. Ramsden’ s fliop, and having each ' 
two brafs pins driven into them at the diftance of twenty feet, 
were laid on the top of the houfe, where they remained until 
the 26th, the weather, for the greater part of the time, having 
been very wet. They were then taken down, and being, by" 
means of the long beam compaffes, compared with the mea- 
fures on the plank, the New-England rod was found to have 1 ' 
lengthened 0.63 1 inch, and the Riga rod 0.041 inch. By which 
experiment the fa£t fee ms to be eftablifhed, that Riga red" 
wood, not withftanding the quantity of turpentine which it 
contains, is more fufceptible of the effedts of moifture than 1 
New-England white wood. Mr. Ramsden likewife finds, 
that the great plank fo often mentioned, duffers,- in ordinary 
fiummer weather, an alternate expanfion and contradlion, 
amounting at a medium to 0.0041 of an inch every day : that 
is to fay, if the difhmce between the twenty-feet brafs points 
be meafured from the fcale, by means of the beam compares, 
in the evening, it is found to have lengthened next morning 
0.0041 of an inch, by the humidity of the intervening night. 
In the courfe of the following day it contracts again to its for- 
mer length, and fo on. Mr. Ramsden has often obferved 
this alternate change:- in the deal plank ; but it was particularly 
on the 1 1 th and 1 2th of Auguft, that the quantity was actually 
meafured. It will readily be underftood, that any difference of 
temperature which might have happened in the brafs fcale, at 
the 
