I 
. Wild Mammals 
100 large color * c _ T ,1 „ . . 
photographs_^^^^^^ oi Northwest America 
by Arthur Savage and Candace Savage 
Did you know that: porcupines can 
sing? beavers build mud pies to mark 
their territories? coyotes and badgers 
sometimes hunt together? wolverines 
have been known to kill bull moose? 
mountain goats make a game of turn 
ing somersaults? These are only a few 
of the fascinating facts revealed in Wild 
Mammals of Northwest America. 
This attractive, informative volume 
— illustrated with more than one 
hundred large color photographs — 
explores the behavior, ecology, and 
natural history of seventy different 
North American mammals. 
The authors combine extensive knowledge with a natural love of the out 
doors to instill in the reader a new appreciation of the uniqueness and 
importance of every animal. They supplement the text with a large selection 
of the finest American and Canadian nature photography, all reproduced in 
living color, and sixty' range maps illustrating the present distribution of all 
of the species. $25.00 through December 31 , 1981 
$27.95 thereafter 
Available at your local bookstore or from 
The Johns Hopkins University Press 
Baltimore, Maryland 21218 
The 1982 Program 
Stimulate your mind on a Questers nature 
tour. We search out the plants and animals, birds 
and flowers ... and explore rain forests, mountains and 
tundra, seashores, lakes and swamps. There is ample 
time to photograph, absorb, reflect. Naturalist guides, 
small tour parties, first-class accommodations. 
Worldwide Nature Tours 
1982 Departures 
The Americas 
Everglades: 11 days, Apr 8. Nov 4 • Hawaii: 15 
days, Feb 14, Mar 21, Oct. 10, Dec 19-Alaska:17 
days, June 12, 26. July 10, 24, Aug. 7 • Pacific 
Northwest: 12 days, June 20, Aug 1 • Superior 
Forest Canoe Trip: 9 days, July 1 0, Aug 1 4 • North- 
west Canada: 16 days, July 2 • Churchill: 
11 days, July 17 • Newfoundland: 16 days, June 13 • 
Baja California: 11 days, Apr 16, Oct 15-Southern 
Mexico: 14 days, Feb 14, Dec 19 • Costa Rica & 
Panama: 16 days, Feb 13, Nov 20, Dec 18 • The 
Amazon: 17 days, Jan 17, May 9, July 4, 
Aug 8, Oct 10, Nov 14 • Galapagos: 15 days, 
Jan 28. Xpr 22, July 15. Aug 5, Oct 28 • Peru: 
23 days, July 17, Nov 6 -Patagonia: 21 days, Nov 6 
• Trinidad & Tobago: 11 days, Mar 8, Nov 8 
Euro pe 
Iceland: 16 days, June 11, July 2, Aug 6 • Islands/ 
Highlands of Scotland: 21 days, May 27, July 15, 
Aug 19 • Switzerland: 17 days, July 16, Aug 13- 
Greece: 19 days, Mar 29, Sept 20 • Spain: 
20 days, Apr 16, Sept 3 
Asia and Africa 
Israel: 16 days, Mar 15, Oct 18 • The Himalayas: 
23 days, Mar 18, Oct 7 • India: 23 days, Jan 30, 
Oct 30, Nov 27 • Sri Lanka: 18 days, Feb 19, 
Nov 19 • Kenya: 23 days, Feb 4. July 22, Oct 21 • 
Zimbabwe & Botswana: 19 days, July 8, Aug 5 
Australasia 
Australia & New Zealand: 30 days, Feb 13, Oct 2- 
New Zealand & the Milford Track: 22 days, 
Feb 12, Nov 12 • The Complete Australia: 
35 days, Sept 3 
To learn more, write requesting the 1982 
Directory of Worldwide Nature Tours. Indicate if 
you are interested in any particular tour and we will 
send the corresponding Detailed Itinerary 
QUESTERS 
Questers Tours & Travel, Inc. 
Dept. NH, 257 Park Avenue South 
New York, NY 10010 • (212) 673-3120 
difficult to separate the brightness of 
Halley’s nucleus from the brightness of 
its coma and thus to gauge the size of 
the nucleus. 
As the comet rounds the sun and 
displays the full panoply of cometary 
phenomena, as I think it will, Halley will 
shed a huge amount of ice, dust, and 
gases. The quantities of each will be 
determined by the many observations 
that are planned. Finally, as the comet 
recedes into deep space, to return next 
in the second half of the twenty-first 
century, it will shed its coma and tails, 
permitting a final glimpse of its born- 
again unadorned frozen nucleus. 
If all goes well, the planned studies of 
Halley’s comet may tell us what a 
cometary nucleus is really like. Al- 
though it is generally believed to be a 
“dirty snowball” of ice and rock dust, 
recent ground-based observations have 
raised some doubts. In fact, one paper 
presented not long ago at a comet con- 
ference in Tucson was provocatively ti- 
tled “Where Is the Ice in Comets?” 
Infrared measurements from several ob- 
servatories indicate that comet nuclei 
have the same general reflective proper- 
ties as many asteroids. Yet asteroids 
have no atmospheres (comets do — the 
coma, or comet head, is an atmosphere) 
and surely are made of rock, while the 
presence of frozen water and other icy 
substances somewhere in the nucleus of 
a comet is proved by the fact that when 
the nucleus nears the sun, the coma 
forms around the nucleus. Current 
thinking holds that volatile materials 
sometimes are shed from the nucleus 
surface, leaving an outer crust of rock 
dust. According to this reasoning, the 
gases that stream outward to form the 
coma of a crusted comet evaporate from 
ices located below the surface of the 
nucleus and flow out of it through tiny 
channels in the crust. This would ac- 
count for the observed infrared reflec- 
tivities and explain the coma, but the 
idea is definitely in need of verification. 
Measurements from a spacecraft close 
to the nucleus of Halley’s comet, if any 
spacecraft gets there, could answer this 
question. One of the problems, of 
course, in approaching a cometary nu- 
cleus is the danger of collision with 
numerous small, or a few large, rock 
particles. 
An early sighting of Halley’s comet 
will help astronomers chart its path 
more closely. In the past, slight devi- 
ations from the expected path have led 
some astronomers to claim that the 
comet was slightly off track due to the 
gravitational pull of an as-yet-undiscov- 
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