MATH WITHOUT TEARS 
Using non technical Language and 
u light touch Roy Hartkonf gives 
you a basic understanding of 
many everyday applications of 
mathematics. He takes the reader 
from simple counting to trlgo 
nometrv and ealrulus. empha- 
sising the practical aspects of 
math. Humorously written. 
Learn math In the comfort 
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imum cost. 
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For the eleventh year we invite fourteen 
discerning travelers who are interested in 
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our leisurely yacht cruises to 
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AUGUST 13 TO 25 and 
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We provide a full week at these unique 
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before the cruise we enjoy three days in 
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Detailed brochures of the cruises and a copy 
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NATURAL HISTORY 
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send the present address label from the maga- 
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r 
(North Scituate: Duxbury Press, 1979). 
Two books by F. Bruemmer are The 
Arctic (New York: Quadrangle/The 
New York Times Book Co., 1973), 
which covers the adaptation to cold by 
arctic plants, animals, and northern peo- 
ple, and Seasons of the Eskimo (New 
York: New York Graphic Society, 
1971), which records the seasonal cycle 
of Eskimo life and cultural adaptations 
to the severe climate. 
Animals 
S.C. Kendeigh’s “Energy of Birds 
Conserved by Roosting in Cavities” 
(Wilson Bulletin, vol. 73, pp. 140-47) 
discusses how birds use this strategy to 
save energy and maintain higher tem- 
peratures during periods of extreme 
weather. Articles on energy-saving tech- 
niques of black-capped chickadees in- 
clude B. Kessel’s “Winter Activity Pat- 
terns of Black-capped Chickadee” ( Wil- 
son Bulletin, vol. 88, pp. 36-61) and 
S.B. Chaplin’s “Daily Energetics of the 
Black-capped Chickadee” ( Journal of 
Comparative Physiology, vol. 89, pp. 
321-30). L. Irving’s Arctic Life of Birds 
and Mammals, Including Man (New 
York: Springer- Verlag, 1972) includes 
chapters on arctic environment, land 
birds and their migration, maintenance 
of arctic bird populations, and warm 
temperatures of birds and mammals. In 
“Physiology of Hibernating Bears,” 
G.E. Folk, A. Larson, and M.A. Folk 
consider whether the term hibernation 
is justified, and review all the conspicu- 
ous papers on the subject (Bears: Their 
Biology and Management, edited by 
M.R. Pelton, J.W. Lentfer, and G.E. 
Folk. New York: Unipub, New Series 
Publications no. 40, 1976). R.A. Nelson 
reviews the physiological and metabolic 
processes involved in hibernation in 
“Winter Sleep in the Black Bear” 
(Rochester: Mayo Clinic Proceedings 
48, pp. 733-37). L. Rogers summarizes 
in six nontechnical pages his knowledge 
of bears, including how they relate to 
people, denning, and cub behavior, in 
“The Ubiquitous Black Bear” (North 
American Big Game, edited by W.H. 
Nesbitt and J.S. Parker. Washington, 
D.C.: The Boone and Crockett Club and 
the National Rifle Association of Amer- 
ica, 1977). B. Ford’s Black Bear: Spirit 
of Wilderness (Boston: Houghton Miff- 
lin, 1981) is a scholarly, up-to-date gen- 
eral book with a good section on hiber- 
nation. PD. Watts et al. propose a new 
definition of hibernation in “Mamma- 
lian Hibernation and the Oxygen Con- 
sumption of a Denning Black Bear” 
(Comparative Biochemistry and Physi- 
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