5. A _New Instrument_, by which the _Refraction_ of all kinds of Liquors may be exactly measured, thereby to give the Curious an opportunity of making Trials of that kind, to establish the _Laws_ of _Refraction_, to wit, whether the _Sines of the Angles of Refraction are respectively proportionable to the Sines of the Angles of Incidence:_ This Instrument being very proper to examine very accurately, and with little trouble, and in small quantities, the _Refraction_ of any Liquor, not only for _one_ inclination, but for _all_; whereby he is enabled to make accurate _Tables_. By the same also he affirms to have found it true, that what _proportion_ the _Sine_ of the Angle of the one _inclination_ has to the _Sine_ of its Angle of _Refraction_, correspondent to it, the same proportion have all the other _Sines_ of Inclination to their respective _Sines_ of _Refractions_. Lastly, this Author despairs not that there may be found many Mechanical Inventions, to improve our Senses of _Hearing, Smelling, Tasting, Touching_, as well as we have improved that of _Seeing_ by _Optick Glasses_. * * * * * London, Printed with Licence for _John Martyn_, and _James Allestry_, Printers to the _Royal Society_. {33} * * * * * _Numb._ 3. PHILOSOPHICAL _TRANSACTIONS._ * * * * * _Munday_, _May_ 8. 1665. * * * * * The Contents. _Some Observations and Experiments upon _May-dew_. The Motion of the _Second Comet_ predicted, by the same person, who predicted that of the former. A Relation of the Advice, given by a _French_ Gentleman, touching the Conjunction of the _Ocean_ and the _Mediterranean_. Of the way of killing _Ratle-snakes_, used in _Virginia_. A Relation of Persons kill'd with Subterraneous _Damps_. Of the _Mineral_ of _Liege_, yielding both _Brimstone_, and _Vitriol_, and the way of extracting them out of it, used at _Liege_. An Account of Mr. _Boyle's_ Experimental _History_ of_ Cold. * * * * * _Some Observations and Experiments upon _May-Dew_._ That ingenious and inquisitive Gentleman, Master _Thomas Henshaw_, having had occasion to make use of a great quantity of _May-dew_, did, by several casual Essayes on that Subject, make the following Observations and Tryals, and present them to the _Royal Society_. {34} That _Dew_ newly gathered and filtred through a clean Linnen cloth, though it be not very clear, is of a yellowish Colour, somewhat approaching to that of Urine. That having endevoured to putrefy it by putting several proportions into Glass bodies with blind heads, and setting them in several heats, as of dung, and gentle baths, he quite failed of his intention: for heat, though never so gentle, did rather clarify, and preserve it sweet, though continued for two moneths together, then cause any putrefaction or separation of parts.