[4J:3 
with the Stench of Water in the Hold, many Men 
being crouded up in Clofe- quarters, all the men- 
tioned Circumftances concur in producing greater 
Mifchief than would follow from any of them 
(ingle. 
The Reafon of thefe bad Effcds is this: It is that 
Property of the Air which is called its Elafticity or 
Springinefs, which makes it fo ufeful to our Life. 
When any Part of it is inclofed and kept from the 
Communication of the outward Air, it expands itfelf, 
and, in Proportion to the Clofenefs of the Place, 
lofes its Spring 5 and if any Heat or Moifture comes 
to it, the claftic Force may be quite loft and deftroy’d : 
And not only fo, but if it happens to be impreg- 
nated with noxious Effluvia, either from unwhol- 
fome Subftances of any kind, or from the infedious 
Breath of difeafed Bodies j it will become quite poi- 
fonous and deadly, in a manner fuitable to the ori- 
ginal Caufe. 
It is propofed at prefent to find out a Remedy for 
this Evil in Ships only : But by making Alterations 
according as particular Places require, the fame may 
be applied to any Houfes or Parts of them, as Prifons, 
the (ick Wards in Hofpitals, &c. 
Now it is a natural Confcquent of the Elafticity 
of the Air, that when it is rarefied in any Part, (which 
is moft effedually done by Heat) the neighbouring 
Ait will rufh that way, till this Part is brought to be 
of an equal Denfity and Elafticity with itfelf 5 and 
this again will be followed by the Air next to it: So 
that, if a Conveyance for Air be laid from the Hold 
or Well of the Ship, and a Rarefadion of the Air 
therein be made j the foul Air from this Place will 
id F 2 run 
