a£d Dippings of the Needle ,, in different places , and in the 
fame place 5 at different times : The Winds 4 Weather, and 
Tempers of the Seafons every where: The great Depths, 
Ground, and Vegetables at the bottom of the Sea : The vari- 
ous Degrees of Saltnefs of the Sea- water , in feveral places , 
and at feveral Depths at the fame place. If befides Aftrono- 
mical things , to be hereafter lookt into, the following Expe- 
riments be -carefully made , and Dire&ions obferved by as many 
Ingenious Perfons , as have opportunity , it may fairly be hoped, 
that from multitudes of Experiments and Obfervations , fuch 
Rules may be framed, as may be of ineftimable ufe for Seamen, 
To which purpofe , the Royal Society , having fome years ago, 
ordered that Eminent Mathematician Mafterifwfo, one of their 
Fellows, and GeomtryVrofcffoYof Grc/ham Co Hedge (fince decea- 
fed , to the great detriment of the Common-wealth of Learning) 
to draw up fome Dire&ions for Seamen , the better to capacitate 
them for making fuch Obfervations abroad, as might be perti- 
nent and fuitable to the purpofes above-mentioned • fuch Direfti- 
ons were drawn up accordingly , and foon after printed in 
Numb, 8, of thefe Trunnions. But, further to encourage 
and facilitate the Work of thofe , that fhall be engaged to put 
them into pradice, it was thought fit, that what of this Kind 
was heretofore but barely propofed , fhould now be publifht : 
with ample and particular Explanations , and confiderable Additi- 
ons 5 which done, a good Number of fuch printed Copies is , by 
the Care, and at the Expences of theR, Society , to be lodged with 
the Mafter of Trinity-Houfe , to be recommended to fuch , as are 
bound for far Sea- Voyages , and fhall be judged fit for the per- 
formance : who are alfo to be defired , to keep an exad Diary of 
fuch Obfervations and Experiments , and deliver at their return a 
fair Copy thereof to the Lord High Admiral of England , his Roy- 
al Highnefs the Duke of Tori', and another to Trinity- ffouje > to, 
be perufed by thefaid & Society , . 
