HI 3 
RO tee 
out after a Eantinwenee of a rainy, 
and ftormy weather; which made it ne- 
‘ceflary to. keep the’ ports fhut, obliged 
the feamen to remain much between 
decks, and allowed them no opportunity 
of drying their cloaths. I was, in con- 
fequence of fuch information, led to en- 
quire and think of the-modes of ventila- 
ting thips; and one occurred to me, which 
I cannot but believe would be very ef- 
fe&tual, requiring no labour, and it 
might.be put in practice at an inconfider . 
able expence, 
The principle of the plan which I pro- 
pole, I find, by looking into the “ £z- 
cyclopedia,” is not new; but I think the 
ynode of accompli thing it, which I pro- 
pofe, could not fave occurred, or it 
would have been carried into execution. 
If Sir, you think well of the plan, you 
_ will oblige me, by procuring its infertion 
tn the Monthly Magazine, as, by this 
_- means, the public may be put in poffef- 
fion of it, and be enab bled to judge of its 
expediency. 
The plan which I offer is extremely 
fnple, it confifts merely j in caufing two. 
tubes to defcend from above the deck to 
the bottom of a vefiel, or as low as ven- 
iilation is required; and which fhould 
communicate by fmaller pipes (open at 
their extremities) with thoie places de- 
figned to be ventilated. There fhould 
_ be a contrivance for ftopping thefe com- 
municating pipes, fo that ventilation 
may be oceafionally prevented from tak- 
ing place, or confined to any particular 
pt of the vefiel. 
Qne of the principal air tubes fhould 
defcend as near to the ftern of the veffel 
__ as convenient, and the other as near to 
the fem. 
‘Ehrough that tube which is in tae 
head, the foul air is to be extracted ; and 
through that which is in the ftern, the 
freth air is to defcend to the different 
decks and other apartments of the 
eftel oo 
vi The extraétion of the air is eafily ef- 
feted, in the following manner: let a 
tran{verfe tube be fitted to that which de- 
fcends jn the head of the veffel ; it may 
be funk ‘within ‘the level of the aes fo 
as to caufe no inequality of furfac ‘Let 
“It be contimued till it comes Baie ty the 
pre pines; then alce nd in a perpendicylar 
Mode of Pentlatng Ships by Mr. Abernethy. 
direétion through the Brey nant open: a 
little above it; or it may be made to 
communicate with the chimney. 
It would be more convenient if the fire 
was near the place where the tube rifes 
through the deck; and, in Indiamen, I 
am told, that the fetid in the forecaftle 5 
but the experiment muft equally fucceed, 
if the tube be made to defcend again till 
it is beneath the common fire-place. 
The effeét that will refult from: this 
contrivance, is obvious; when the tube 
which paffes through the fire, is heated, 
the air will afcend “with a force propor- 
tionable to its levity, and the afcendi 
cqlumn can only be fupplied from below; 
confequently it muft come from all thofe 
parts of the hip with which the main 
tube communicates. ’ 
When the ports are open, the quantity 
of air thus exhaufted from the fhip, will 
be fupplied from all quarters; but if 
they were all fhut, and the hatchways 
and other openings completely clofed, the 
renewal of frefh air is made certain b . 
means of the tube which defcends in the 
ftern. The main air tube, where it rifes 
above. the deck in the ftern, fhould; I 
think, have an horizontal one fitted to 
it, which might be made to travertfe, {o 
that it could be turned to windward; it 
might alfo expand at its extremity like 
the mouth of a trumpet ; and thus per- 
feGtly frefh air muft enter, and the forge 
of the gale would tend to impel it into 
the veftel. 
When that part of the tube which 
paffes through ‘the fire, is red hot, the 
draught which would be thus occafioned, 
might, perhaps, be too great, and the 
open pipes which communicate with the 
decks, might emit and imbibe the frefh air 
in fo direct a ftream, that it might be 
injurious to thot: eet fons within the cur~ 
Tents 
IT therefore think it would be dices if 
thofe fmaller pipes which lead from the 
main tubes were made to run along the 
decks, and communicate with them by, 
numerous orifices. Iwo pipes opening 
into the main exhaufting tube, might»be 
extended along the tops of the deck,:in 
the ‘angle formed between the fides and 
the cieling : and thus the air would be 
extraéted “equally from all parts, and in 
a manner not likely to occafion injurious 
currents. Some divifion of the-ftream of 
air which enters from the ftern, might 
alfo be made, if it were thought neceflar Ye 
“Thus, I imagine, a very complete, and 
vs » 4 
