(44«) 
7« To ohfervie and record all Extraordinary Me- 
teors, Lightnings, thunders, Ignes fatuos. 
Comets^ 6cc. marking flill the places and times 
of their appearing, continuance^ &c. 
To carry mth them good Scales and (jlafs Vt^ 
ols of a pint or fo , rt>ith 'very narroT» mouths, 
ifhich are to be fill'd mth Sea-water in diffe- 
rent degrees of l^QiUiM^t , and the vpcight of 
the Viol full of 'water taken exaBly at every 
time J .and recorded ^ marling yeithal the de^ 
grees of Latitude and Lengitude of the 
Tlace , and the T>ay of the zfMoneth, and 
the Temperature of the JVeather : And that 
M mll of W %ter near the Top, as at a greater 
"Aepth. 
THe Viol is to be made with a very narrow Neck , and when it 
^ is almoft full , water is to be dropt into it , drop by drop, till 
it can hold no more , drying well the Viol before it be weighed. 
The weight of th? empty Viol is alfo to be recorded eyery time, 
weighing all to grains. Andby evaporating gently the water , till 
the Salt beleftdry on the bottom; they,wholift, may have the 
fatisfadionto know, what proportion the Salt of each water hold- 
cth to its weight. 
There is, among feme other wayes of finding the different gra- 
vities of Water , a very pretty one , mentioned by fome Authors, 
as Johmnes Toldenm (a German Artift) Cabins ^ aad Klrchtr in 
his 
