C ;8° : 
Urinatoria , with the ingenious Improvements of Dr. 
Halley ; yet I have likewife found, that this Inven- 
tion is not to be made ufe of without confiderable 
Charge, requiring a large Velfel, and Number of 
Hands, to the working and managing of fuch a large 
Diving Bell, and the Air Barrels with their refpe&ive 
Weights for finking 5 which Charges, however, ac- 
cording to the Depth of Water, and the Value of 
what is to be fetch'd up from the Bottom of the Sea, 
may not be regarded : But fince it more frequently 
happens in thefe Parts, that Cargoes of a far lefs Value 
than the Loadings of Spanijh Galleons, &c. are to be 
dived for 5 then next to the Goodnefs of the Inven- 
tion, I have found myfelf neceflltated to think how 
the Expences might be leffen'd, and that the Diving 
Bell neverthelefs might anfwer all Intents and Pur- 
pofes of Dr. Halley’s 5 which Improvement I take 
herewith the Liberty to communicate to you, which, 
is as follows : 
The Diving Bell, A B. {fee Fig. I.) I have caus'd 
to be made of Copper, and reduc'd the fame to a very 
little Compafs in regard to that of Dr. Halley’s , as 
you'll fee by the Scale under the Draught, by which 
means it is eafily managed by two Hands : Yet I pre- 
fume that a Diver may not only live in the fame for 
as long a Time, and with as much Eafe, at a very con* 
fiderable Depth of Water, as in a Bell of twice its Ca- 
pacity, for this Reafon, tho' a Man in a large Bell has 
undoubtedly more Air than in a lefs, and confer 
quently fhould be able to fubfift a great while longer 
on a large Quantity of Air than on a fmall Parcel ; yet 
becaufe his Head for the moft part is kept in the upper 
Part of the Bell, where the hot Air takes up its Place 
and 
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