( 4 8 ? ) 
Give me leave hereto refledt a iittle upon the iate 
Aurora Borealis, whole Phenomena you have fo well 
defcrib’d and explain'd in your late Philofophical Tranfa&i- 
on, No. 347. 1 am of your Opinion, that thofe Phos- 
phorous or Luminous Appearances in the Firmament, 
proceed from the various Effluvia perfpird out of our 
Globe, or palling thro’ it? for 1 have feen thofe Lights 
over Ve fuvius, the Strombulo lllands, and towards JEtna 
in dark Nights, when thofe Vulcanos were not flaming 
nor burning, their Sides and Tops being palfable to Tra- 
vellers at that time, and all their outward parts quiet. 
We are certain that Iceland and Greenland abound with 
Vulcano’s ; fo may North Eaft Lapland, North Raffia and 
Tart ary, where vaft Chains of Mountains are faid to run. 
The Jejuits, and other Travellers, relate many prodigi- 
ous Eruptions of Fires, and Earthquakes towards the 
North of China ; but nearer the Pole the Earth mult be 
clos’d and pent up many Months, by the long fevere 
freezings and continual Snow and Ice, which relaxing 
towards Spring, may give vent to that vaft Mafs or Ma- 
gazine of perlpirable Matter, that had been kept fo long 
in hot Subterraneous Prifons. This may be one Reafbn 
why Animal Bodies themfelves are often fenfible of 
Changes at that Seafon in our Climate, when Perfpiration 
is upon fuch an Increafe •, but 1 will not take up your 
time any longer, efpecially upon a Subject that you un- 
derfland fo well. 
SIR, 
Tour mo ft humble Servant , 
Tancred Robinfbn,. 
IV. An 
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