The Book of Clouds by John A. Day
Reviewed by Duane Dunkerson
The subjects of this book are the bane of astronomy. They are
only ice crystals or water droplets. They have marvelous shapes
and lovely forms. They are beautiful and terrifying. Dynamic swirls,
fluffs. A show. A science. Never the same. They sport coming attractions.
They are the clouds.
They are part of the water cycle. If you, on a cloudy day, are
above a stream on a humid day as waves of moisture waft aloft
after a very recent rain; then you are in the water cycle.
Mr. Day has grouped the clouds by shape and named them by shape
and for the weather conditions they signify or foster. Many large
magnificent photos of these always transient phenomena are in
this book. The photos show them to be so thin at times, like ghosts.
Yet these ghosts are of water and water is a dominant part of
Earth's area and unique in being capable of being solid, liquid,
and gas. The boiling and melting points aren't normal. We are
mostly water. And water floats, oddly less dense as a solid.
Clouds are water held in the air, supported in air. Differing
amounts of water vapor in warm vs cold air is critical to cloud
formation. Droplets remain above Earth, smaller than rain drops.
Each of these droplets requires a seed to grow from such as an
aerosol or dust or soil or minerals.
By the millions the droplets form into clouds. Mr. Day notes
that they can be cumulus in classification with domes and towers.
They can be seen as puffs or in cauliflower shape. He mentions
how high is the base and how high is the top. He tells us of their
air mass stability, buoyancy, moisture content, temperature, frontal
lift, and precipitation type. He carries over these characteristics
to stratus cloud - those clouds lying on the Earth, ground fog
of mists, shrouds, and obscuration. Next are the mixing of cumulus
and stratus in transitional forms. There are heaps and layers
or rows. Ripples happen Agitated convection is frequent. Mackerel
skies and buttermilk skies are found in this grouping. Then there
are the precipitating clouds that can be heavy showers, light
showers, or drizzle and then snow too. Also you sometimes expect
hail or the dreaded tornado.
Mr. Day includes photos of rainbows, halos, sun dogs, the pastels
of irisation, and coronas. More photos show rays of sunlight and
the green flash. Unusual clouds are also photogenically represented
with, for example billows, lenticulars of colorful beauty and
wondrous form, and cap clouds over mountain peaks. Noctilucents
are found shining at night at very high, very dry, altitudes of
250,000 to 300,000 feet and are rarely seen. Sea smoke is shown
that give rise to tendrils of fog when very cold air drifts across
warm water. The funnel cloud, not always destructive but usually
associated with tornados, is pictured. Other oddities are the
mammatus clouds like tennis balls hanging on the underside of
other clouds and Kelvin-Helmholtz clouds, products of wind shear
at the boundary of warm vs cold air are depicted. There were no
photographs and no names in classification for the clouds until
In 1802 a pharmacist interested in meteorology, Luke Howard,
presented his ideas for the classification of clouds to the Askesian
Society in London. Before, this, people had put clouds in paintings,
books, and poems as angelic or animalistic in shape or as an accepted
part of the unexplained sky.
Before and since 1802, no matter what they are called, the usual
astronomer did not or does not welcome the nighttime clouds. They
were and are usually cursed at by the telescopist since nothing
or less than the best can be seen through the intervening clouds.
Adaptive optics can equal telescopes placed in orbit but the applied
technology to remove the atmospheric annoyances of a cloudy night
does not yet exist.
One can sometimes observe along with the clouds, giving them
their due if the clouds move along and permit at least intermittent
use of the telescope. If the Moon provides enough illumination,
you can observe the Moon and enjoy the ephemeral clouds. Usually
you can see the clouds in sunlight but nighttime illumination
offers appreciation of their forms and function along with, perhaps,
some indulgence in astronomy.
Should you not be a lunar observer or are unfortunate in having
night like day due to commercial, industrial, military, or security
lights in your area, then such clouds as can be seen at night
represent for you inadequate compensation for a hobby not to be
For lunar observers, they can, if they so desire, use this book
to learn what clouds obscured the view from time to time. They
could also learn why the clouds were there, why they assumed the
shapes they did, and why they may have more such visitors in the
sky the next night. They could also learn that earlier daytime
clouds could have forecast conditions for their nighttime observing
In 1922, Lewis Richardson's book, Weather Prediction by Numerical
Process, was demonstrating how to grid the weather data and enter
into predictions but Mr. Richardson didn't have the 64,000 people
he would have needed to do the computations for him. Now computers
can do it. Even so, highly accurate longer term forecasts are
not generally possible even if supercomputers are used.
Mr. Day offers do-it-yourself forecasting done with a barometer
and knowledge of cloud types. So then, for your locale, you can
know when rain will occur in 12 hours, or if it will be cloudy
in 24 hours. So too you can be aware of an approaching cold front
or a warm front, and know if it should be fair or if you should
soon seek shelter.
Mr. Day also offers tips on photographing clouds. Nearly all
of his photos are of daytime formations. Moon and clouds as a
compound subject would be of interest and if you are at the scope
waiting for cloud passage, then snap a few photos. Don't complain
about it, photograph it.