Why We'll Never Run Out of Letters
"WHY WE'LL NEVER RUN OUT OF OIL"[JUNE] does not address the real issues concerning oil consumption. Although we're not running out of oil per se, we are running out of cheap oil. As the global population booms and the standard of living rises, more people will be competing for less cheap oil. In 1950 the United States was producing half the world's oil; today America can't even produce half its own petroleum needs.
Now is the time to prepare for a graceful transition, lest the end of cheap fossil fuels be an unprecedented disaster in human history. Think of your children's children's children. What legacy do you want to leave--health and abundance, or a depleted, sickened world?Dohn K. Riley TAHOE CITY, CALIF.
It does not make any sense to convert natural gas into a more complicated and "dirty" fuel just so we can keep using current internal combustion power sources.
It is apparent that those who decide what resources to use, and how, intend to profit with the least amount of change to the established system. Change will be left to the rebels among us in the engineering and business arenas who see the opportunities inherent in intelligent use of what we were given. Robert Wells SETAUKET, N.Y.
Your sidebar on the history of the petroleum industry shows a bit of a U.S.-centric slant. "Colonel" Edwin Drake may have drilled the first modern oil well in the United States, but the strike at Petrolia, Ontario, preceded the Titusville strike by two years. Incidentally, Petrolia is still a producing field, although only in minor quantities these days. Marc and Kathleen Schindler SPRUCE GROVE, ALBERTA
The beautiful images shown in "X-ray Stories" [May] demonstrated, as you wrote, "why X-rays retain their usefulness in an age of CT scans, MRIs, and high-tech imaging." The use of CT scans should not be discouraged when the benefits are clear, but it should be noted that CT uses truly scary X-rays. Abdominal CT scans cause 12.5 cancer deaths per 10,000 persons exposed to a single examination, comparable with yearly smoking-induced deaths at 12 per 10,000 smokers. Currently, in the United States about 35 percent of all medical radiation exposure now comes from CT scans, which make up about 5 percent of all medical examinations that use radiation. This is estimated to cause at least 2,600 cancer deaths in the United States per year. The simple film X-rays shown in the article still retain many advantages.Everett M. Lautin, M.D., F.A.C.R. NEW YORK, N.Y.
A Kinder, Gentler Shark?
I have read survivors' chilling accounts of the large number of men taken by repeated shark attacks following the sinking of the USS Indianapolis toward the end of World War II. I suspect that this incident alone would invalidate the shark fatality figures you quote in your article ["The Great White's Ways," June]. The Indianapolis attacks seem to indicate that the shark is not at all hesitant to prey on humans if the situation presents itself.Kevin Gray THOUSAND OAKS, CALIF.
George H. Burgess, Director, International Shark Attack File, replies: The tragic sinking of the USS Indianapolis occurred in tropical waters not normally inhabited by white sharks, which generally prefer cool, nearshore waters. First-person accounts from survivors specifically identified the oceanic whitetip shark as being present during the four days and five nights they spent in the water. That species and perhaps other pelagic sharks, such as the blue shark and silky shark, were likely the perpetrators involved in the attacks and the scavenging of floating human corpses. Although attacks on living survivors occurred with some regularity, the greatest shark damage was inflicted upon the bodies of seamen who already had succumbed to injuries sustained during the sinking of the ship and from the prolonged effects of dehydration and exposure. Circumstances surrounding a major marine catastrophe of this nature, including the thrashing and shouting of survivors, the presence of blood and other bodily fluids, and corpses in the water serve as powerful attractants to sharks. Put simply, the sharks took full advantage of a lengthy feeding opportunity, compounding the tragedy of the Indianapolis sinking and the subsequent loss of life attributable, in large part, to lengthy delays in rescuing its survivors.
Letter to Tomorrow
I thought the sample messages you published in your article about KEO, in the June issue, were a bit too artsy and French, if you catch my drift. I asked a couple of my colleagues (engineers) what they would say to people 50,000 years from now. They delivered the following: "Have the Cubs won the Series yet?" "Please unfreeze my head." Jim Glass CHATSWORTH, CALIF.