TRANSACTIONS OF THE SECTIONS. 189 
able voyage being between England and America 22 days, and her 
favourable voyage 14 days, being a comparative velocity of 7 and 11. 
2 — y!2 12] — 49 72 
‘h ‘— Beira ae ——————— ee OP as es 
Then h'=2h s 2 i291 2 12] 
= 12 nearly. 
10 
Hence the power should be increased in the ratio of 6 to 5; that is 
to say, the engines at present capable of exerting a power of 500 horses 
should have been capable of exerting a power of 600 horses, and would 
in this case consume less fuel, as well as produce greater regularity and 
a higher velocity.” 
The following results also follow :— 
“The vessel of less power burns 30 tons per day, performs the di- 
stance in 14 days, consuming 420 tons of coal in fair weather. 
“ The vessel of less power burns 30 tons, performs the distance in 22 
days, consuming 660 tons of coal in foul weather. 
“The vessel of greater power burns 36 tons, performs the distance in 
123 days, consuming 468 tons in fair weather. 
“ The vessel of greater power burns 36 tons, performs the distance in 
17°5 days, consuming 630 tons in foul weather, being a consumption of 
64 tons less fuel, and performing the journey in 43 days less than the 
other. 
“Tt is manifest, that the store of fuel carried in the vessel with less 
power must on all occasions be equal to the greatest consumption, that 
is, to at least 660 tons, whereas 630 tons will be sufficient for the vessel 
of greater power; and as in all vessels for long voyages coals carried 
are much more costly than the mere price of coals, or as the freight of 
the vessel is more costly than the fuel, coals carried are to be reckoned 
at least as expensive as coals burnt. Moreover, as the gain in time is 43 
out of 22, being 25 per cent., it is plain that the vessel may be calculated 
to do the distance oftener in a year, because, as the time of starting 
must always be regulated, not by the shorter, but by the longest period 
of a voyage, 174 days in the one case stand in the place of 22 days in 
the other. As another example, let us take the case of a vessel calcu- 
lated to stem the monsoon in the Indian Seas. A vessel of 600 tons 
and 200 horses, steaming in fair weather at the rate of 11 miles an 
hour, has been found to have her speed diminished by the monsoon to 
five miles an hour. What would be the best proportion of power in 
such circumstances ? 
Wi = 2h 
v? vy? 112 — 5? 
=) 
v 11° 
= a nearly. 
“Hence we see that the power being increased in the ratio of 16 to 
10, that is, engines of 320 horses power being substituted for those of 
200, the speed on the quick voyage would be 123 miles an hour in- 
stead of 11, and the speed against the monsoons increased from 5 to9 
