Report on the Trade in Animals. 
233 
Although live stock are carried on deck as well as in the holds, 
the owners much prefer the former method. The deck, however, 
is usually reserved for horses, so far as the space is required ; and 
in the event of room being still available, the preference is 
generally given to sheep and pigs, except when a very large or 
very liberal consignor secures it for his beasts. It is important 
to understand that it is a great advantage to secure deck-places 
for cattle, because this knowledge enables one to appreciate the 
conditions which require amendment in the sea-conveyance of 
live stock. The officer of the watch on one of the steamers 
plying between Drogheda and Liverpool — a passage of about 
twelve hours — told me that the cattle on deck would fetch in 
the market at least \l. per head more than they would have 
done if they had been in the hold, whereas the charge for convey- 
ance was less than half this sum. On this occasion there were 
not a large number of cattle in the hold, but they raised the 
temperature from 70°, at which my registering thermometer 
stood on deck, to 80° in the hold near the hatchway. Several 
observations of the temperature of the holds of cattle-boats gave 
about the same result, the index never falling below 79°, nor 
rising much above 80°. 
The mode in which the ventilation of the hold is usually per- 
formed will be understood by reference to the longitudinal section 
of an ideal steamboat (Fig. 3, p. 234), in which the ordinary 
metal " ventilators" or " windsails " are alone used for the purpose. 
This diagram indicates the fact that mere "openings" do not 
necessarily produce currents of fresh air, but that the proper 
removal of vitiated air from the holds, and its renewal by fresh air 
through the agency of the windsails, depend upon the concur- 
rence of several favourable conditions. First of all, it is necessary 
that the mouth of the ventilator should be kept in a position to 
receive the wind, and thus make its shaft a more or less powerful 
" down-cast" or supply-pipe of fresh air. If this is not done 
carefully, it is obvious that the supply of fresh air to the hold 
must very soon be practically stopped. The same result must 
follow during the time that the steamboat is at anchor or moored to 
a wharf, or when there is little or no wind. This not unfrequently 
happens in the case of the Cork steamers, which have to wait for 
the tide at Passage from one to four or five hours. It is also 
the case when the steamer is slowly feeling its way up a tortuous 
river, such as the Avon from Kingroad to Bristol ; for, however 
attentive the crew may be, their other duties do not allow them 
time to shift the ventilator with every change in the course of the 
steamboat along a winding stream. 
In the second place, the amount of air conveyed into the 
hold by these ventilators is dependent upon the relation existing 
