C 38; 3 
in his Mouth, which he may do with all the Eafe in 
the World, yet that the Air would circulate thro' the 
Copper Tube, and he receive no fmall Benefit by it. 
DDDD are the Weights for finking the Bell, fo 
contriv'd as with great Eafe to be hook'd on the fame 
hanging on the Cable. The Iron Plate E, fixed to the 
Chains F F F, ferves the Diver to (land upon, when 
he is at work. 
The Bell is extremely well tinn'd within all over j 
and as in all Rivers, and the Coafts of the Baltic Sea , 
the Water is extremely clear and bright, becaufe of no 
Ebb and Flood, I have plac'd three ftrong convex 
Lenfes G G G. By thefe means the Diver can not only 
fee what is under him, but likewife on all fides at a 
good Diftance. 
Thefe Gaffes have ftrong Copper Lids like Snuff- 
boxes, HHH> which Lids are fhut, when there is no 
Occafion to difcover any Obje&s on the Bottom of the 
Sea, and ferve to preferve the Gaffes from being 
broken. 
I hope you'll pardon the Liberty I have taken to 
trouble you with a long Letter, which I might have 
inlarg'd with an Account of other Inventions, which,, 
if you approve of this, fhall in a little time follow $ 
in the interim I beg you'll grant me leave to remain 
with much Refpeft, Mojl Reverend SIR , 
M. Triewald, 
F R* S, Berl and Swed 
humble Servant . 
IV, A 
