t 6 94 ] 
rifes no more; the Water to have Vent at the Bot- 
tom, yet fo as to have the Gun-barrel always full 
of Water 5 the Breech-Pin to be out, and the leaden 
Rod to reft on a Piece of Wood fet upright, ac- 
cording to the Courfe of its Fibres, not fideways. 
To give at the fame time to a Mercurial Thermo- 
meter the Heat of boiling Water. 
Then to take the freezing Point of the Leaden 
and Mercurial Thermometers ; and afterwards to 
graduate all the intermediate Degrees, from the 
Mercurial Thermometer upon the Leaden Thermo- 
meter, as .they occur. 
Thus a Standard Thermometer may be made to 
graduate others by 5 but I will not now fet about 
it, fince you have undertaken the Subjed. 
His Remarks on the foregoing Paper. 
Page. 673 . Thermometers muft be of excellent 
Ufe in Garden-Stoves $ but foreign Plants muft nor 
be kept in an equal Degree of Heat in Stoves, to 
that of their native Country; viz. becaufe they can- \ 
noc bear as great a Heat in a confined clofe Air, 
as in an open free Air. I have been told of Coffee- 
Trees being killed here in England by this Miftake : 
Such Plants muft doubtlefs be kept warm *, but not 
fo warm as in their native Country. 
P. 
* I fhould think it belt to ieflen the Heat in Stoves towards the Night, 
and fo to keep the Plants expofed to lefs Degrees of Heat a*nights than 
a days, nay to vary the Heat daily, or to endeavour by Art to procure 
different Degrees of Heat, agreeable to the natural Vicijffitudes of the 
Climate the Plants come from, having Regard both to the Seafons of 
the Year, and the State of flowering or Fru&ification of the Plants ; fo 
that the belt Way of ranging Plants in Green-houfes or Stoves is accord- 
ing to the Climates they come from ; for which Mr. Sheldrake's Tables 
above-mentioned, p. 674. muft be of excellent Ufe., C. M. 
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