54 
THE GUIDE TO NATURE 
In Figure 2 are shown the portions 
of the twenty-four hours which are 
night (in black), daylight and twilight, 
in the different months of the year, for 
latitude forty degrees. From this figure 
may be read the times of sunrise and 
sunset and the duration of twilight. 
The twilight is shortest about March 3 
and October 1 and longest at the sum- 
mer solstice, June 21. Its length varies 
from an hour and thirty minutes to two 
hours. The figure shows that the day- 
light decreases from fifteen hours one 
minute at the summer solstice, June 21, 
to nine hours nineteen minutes at the 
winter solstice. December 22. 
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Daylight Saving. 
The purpose of the daylight saving 
scheme is that we should sleep during 
the hours of darkness and reserve the 
daylight for our activities. During the 
winter when the days are short we ordi- 
narily do this, but during the summer 
we do not. From May 1 to August 3. 
for instance, the sun rose earlier than 
five o’clock. Those sleeping as late as 
five o’clock wasted the daylight and the 
morning twilight too. The twilight, 
however, is less important, not only 
because the light is less intense but 
also because some of the twilight time 
must be used to secure eight hours of 
sleep. 
The reasons for daylight saving time 
exist principally in the middle latitudes. 
At the equator, for instance, the sun 
rises at nearly the same time each day, 
varying only from 6:11 A. M. in Feb- 
ruary to 5 :qo in November. There is 
no reason for a time in part of the year 
different from that in use in the other 
parts. In high latitudes where there is 
a great variation in the time of sunrise 
throughout the year there is also little 
need of daylight saving time. In Figure 
3 the times of sunrise and sunset are 
shown for the equator and for a latitude 
of sixty degrees, which is about the 
latitude of the southern coa-^t of Alaska. 
At the latter place the change from 
short days to long days is very rapid. 
The sun rose at six o’clock on March 20 
and at five o’clock April g. 1 he days 
increased nearly two hours in length 
in this brief interval of twenty days. 
When the days are short the daylight 
would all be used as here in winter. 
When the days are long there is more 
davlight than can be used, so that con- 
servation is not necessary. Farther 
north there is still less need of daylight 
saving plan. At the pole itself, where 
it is about equally light or dark 
throughout the twenty-four hours, it 
matters little when one sleeps. 
If the hours from 8 P. M. to 4 A. M. 
were devoted to sleep the daylight 
r 7 r 
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Figure 3. Times cf sunrise and sunset 
at equator and in latitude sixty degrees. 
would be conserved everywhere. There 
is. however, a human disinclination to 
rising before the sun. “Early to bed 
and early to rise” is a good rule — for 
the other fellow. Hence we have 
adopted habits suited to winter rather 
than the whole year and the habit once 
formed of doing things at definite hours 
we object to change. If the sun is shin- 
ing we do not object to rising earlier 
in itself but after rising at seven we 
hate the thought of rising at six. If we 
call it seven we are satisfied provided 
the hours of duty are also set forward, 
for it would be difficult to rise before 
our duties compelled us to. The whole 
reason for daylight saving time is thus 
a psychological one. 
^ ^ ^ ^ ^ 
The New Celestial Object. 
For a few minutes before and after 
sunset on August 7 a celestial object 
brighter than Venus was seen near the 
sun by five observers at the Lick Ob- 
servatory. The number and character 
of the witnesses make the reality of 
the observation unquestionable. The 
object was three degrees east of the 
sun and one degree south of it. The 
object was believed to be either the 
nucleus of a comet or a nova (new 
star). In either case it was a very re- 
markable object. The great comet of 
1843 was discovered very near the sun 
