gs Mr. iienly’s 'Experiments and 
its expart five power in fuch manner as t ce to the 
fmalleft fragments the plate of glafs then i pofed to its 
violent operation, adly, This violent effort of the eledtri- 
city produces not the leaft effedt upon the lurface of the 
flip of paper painted with lamp-black and oil, or upon a 
flip of oiled filk, placed in the fame fituation. 3dly, May 
not therefore a coating of lamp-black and tar, or lamp- 
black and oil, be in fome cafes ufefully applied on flight 
buildings of Wood, See. to preferve them from damage 
by lightning, as well as to prevent thofe large cracks and 
rents (the ufual effect of the heat of the fun) from being 
made in them ? 4thly, As the effedt of the lightning on 
the mafts of fliips has been in fo many inftances pre- 
vented by a coating of lamp-black and tar, or lamp-black 
and oil, it feems probable, that a fafe and fixed con- 
dudtor might be applied to them in a very cheap and 
convenient manner, as follows ; viz. let all thofe parts of 
the mail which are ufually greafed, be provided with 
plates of metal three inches broad, which plates might 
extend a few inches upon the other parts of the maft 
which are coated with lamp-black and tar, or lamp-black 
and oil; and thus by the condudtor of metal, and the 
protedlor of lamp-black and tar, placed alternately and 
extending the whole length of the maft, it would pro- 
bably be preferved from damage by lightning. A 
metallic 
