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have made the whole Tour of Italy , which has 
enabled me to make many Obfervations relating to 
Natural Philofophy. 1 have made fome Experiments 
at the Grotto del Cani > near Naples , which rake off 
a good deal, in my Opinion, of the Marvellous of 
that famous Phenomenon. I propofe to myfclf the 
Honour of tranfmitting them upon fome future Oc- 
cafion, as my Letter is already too long. The 
Eructations from Vefuvius were very great when I 
was there, and were the Prelude to three Earthquakes, 
which happened juft after my Departure, and which 
I was fortunate enough not to be Witnefs of. 
The Lagiines of Venice , and the Waters of the 
Mediterranean Sea, appear luminous every-where 
in Summer, in dark Nights : I have difeovered, that 
this Light proceeds from a very lmall Infect, which 
multiplies prodigioufly. I have heard all my Life, 
that the Water of the Ocean appears fometimes 
luminous : It may poflibly proceed from the lame 
Caufe, and I fhould be very glad of a particular 
Inquiry into this Faff. I have the Honour to be, 
with the molt inviolable Attachment, 
My Lord Duke, 
Tour Grace’s 
Moft humble and obedient Servant , 
The Abbe Nollet. 
An 
