Hese Transactions being intended, not only to be (by parcels) brief Records of the Emergent Works and Productions in the Universe; Of the Mysteries of Nature of later discoveries; And, of the growth of Useful Inventions and Arts; but also, and chiefly, to sollicite in all parts mutuall Ayds and Collegiate endeavours for the farther advancement thereof: we shall begin this Second year of our Publications in this kind (in which, for 3. moneths the Printing-presses were interrupted by the publick Calamity) with a few more particular Observations upon the Ballance of the Air; as they are most happily invented and directed by Mr. Boyle; and deserve to be prosecuted with care and diligence in all places.

But it is to be premised, that that Worthy person, who was alledged as the Author of the Observations, delivered of this kind in the last of these Tracts (Dr. Beale) gives notice, That