7* To obferve and record all Extraordinary Me- 
teors, Lightnings r c : T bunders , Ignes fatuos* 
Comets, &c. marking fltll the places and times 
of their appearing , continuance y <Stc. 
t8. To carry with them good Scales andCjlafs - Vi- 
ols of a pint or fo , narrow mouths 7 
which are to he fill'd with Sea-water in dijfe - 
rent degrees of Latitude * the weight of 
the Viol full of water taken exattly at every 
time , recorded • marking withal the de~ 
grees of Latitude and Longitude of the 
Tlace , and the Lay of the zSAdoneth, and 
the Temperature of the Weather : And that 
as well of Water near the Top > as at a greater 
Depth. : 
T He 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 
ic can hold no more, drying well the Viol before it. be weighed. 
The weight of the empty Viol is alfo to be recorded every time, 
weighing all to grains. And by evaporating gently the water , till 
the Salt be left dry on the bottom *, they, who lift, may have the 
Tatisfa&ion to know, what proportion the Salt of each water hold- 
iCth to its weight. 
There is, among fome other wayes of finding the different gra- 
vities of W ater , a very pretty one , mentioned by fome Authors, 
as Johannes Teldent# (a Germm Artift) Cabas # , and Kircher in 
his 
