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2. Whether different Load-stones will give different Directions? And whether fainter or stronger touches upon one and the same Magnet, will cause any Variation in the Directions? For which purpose, as many Load-stones should be procured, as could be had, and a good number of Needles exactly made, of the same Metal, bigness, and figure?
PROPOSALS
To try the Effects of the Pneumatick Engine exhausted, in Plants, Seeds, Eggs of Silkworms.
The Ingenious Dr. Beale did formerly suggest, as follows.
It would be, I think (saith he) very well worth the tryal, to see what Effects would be produced on Plants, put into the Pneumatick (or Rarifying) Engine of Mr. Boyle, with the Earth about their Roots, and flourishing; whether they would not suddenly wither, if the Air were totally taken from them. And particularly to try in the Season, Cherry-Blossoms, when partly opened, partly not opened, upon a Branch; to wit, whether the Air may be so attenuated as to blast. But it may be noted, that the Blossoms do not forthwith discover the blast: An old experienced Country-man having once given me notice of a blasty Noon, (it being then a Sultry weather, and somewhat gloomy with the thickness of Exhalations, almost like a very thick Mist) and within a day or two shewing the proof upon the Cherry-Blossoms then flagging, but not much altering their Colour till two days more were past.
The Noble Mr. Boyle suggests as proper for the approaching Season; That it may be tried,
1. Whether Seeds (especially such as are of a hasty growth, vid. 0rpin, Lettice, Garden-cress-seeds, &c.) will germinate and thrive in the exhausted Receiver of the said Engine?
2. Whether the Exclusion of Air from the Sensitive Plant, would be harmful to it?
3. Whether the Grafting of Pears upon Spina Cervina (the almost only Purgative Vegetable known in England) will produce the effect of communicating to the Fruit that purging quality, or not?
4. Whether Silkworms Eggs will be hatched in such an exhausted Receiver, in the Season proper for hatching?
