March 15, 1997

Letters

Change in charge adds to clumping?

In "Alcohol's electric effects" (SN: 1/11/97, p. 31), the authors have not taken into account alcohol's ability to cause the red blood cells to agglutinate. Perhaps Gross' observation of the change in electric charge in the cells is an added cause of those cells' tendency to clump and form the so-called sludging that blocks capillary circulation in the brain and disturbs function.

Incidentally, this sludging can be prevented and reversed by anticoagulant therapy, which can prevent or reverse alcoholic brain damage if the condition has not been present long enough to cause the death of the neurons.

Arthur C. Walsh
Pittsburgh, Pa.

Why moonlight may not heat poles

In "Earth's poles feel warmth of the full moon" (SN: 1/11/97, p. 22), there is no indication whether both poles are affected equally. During the Northern Hemisphere summer, the North Pole experiences continuous sunlight. Since the full moon is opposite the sun, the pole experiences almost no moonlight for a few days around full moon. The reverse is true during the Northern Hemisphere winter: The sun doesn't rise in the far arctic regions, but the full moon is visible continuously.

The duration of continuous visibility or lack thereof changes throughout the moon's 18.6-year precessional period, so the 17 years' worth of data may not show this variation. If such variations are not evident, then I would think it points toward some heating mechanism other than direct moonlight.

John Holtz
Coraopolis, Pa.

Long ago, when north was south

"The Lost Tribe of the Mammals" (SN: 12/14/96, p. 378) states that multituberculate discoveries in the Southern Hemisphere have been "extremely spotty" to date, then cites finds in Madagascar, Argentina, and Morocco. "Spotty" indeed, as Morocco is quite firmly in the Northern Hemisphere.

Tobias N. Boyd
Lincoln, Neb.

I am guilty of oversimplification. During the late Jurassic and Cretaceous periods, Africa was part of a southern supercontinent called Gondwana, which also included South America, Australia, Antarctica, and the Indian subcontinent. Because Gondwana sat to the south of the other supercontinent, Laurasia, geologists consider the former pieces of Gondwana as southern landmasses. -- R. Monastersky