We take issue with the physics of skating as described by John Couretas' article on Holger Wurthner's T'blade composite ice skate blade [``Composite blade's design makes for smoother skating,'' Page 1, June 24]. Couretas states, ``Skating friction heats the blade'' and then ``the heated blade melts a thin layer of water, allowing the skate to glide across the surface.''
Skates do glide over ice on a thin film of liquid water, but while frictional heat may contribute slightly to the creation of this water film, it is a physical property unique to water that really makes skating possible.
The molecular structure of water is such that unlike other liquids, it expands in volume when it freezes. This increased volume per unit mass is what makes ice float in liquid water, for example.
The inverse of this property also holds - when ice is compressed, the reduction in volume forces it to melt back into liquid water. This is the key to skating physics.
A sharp blade allows the skater to translate his body weight into a very high local pressure, thus forcing better melt and assuring a good film of liquid beneath the blades.
Wurthner claims his blade retains more heat than an ordinary skate blade, and while this may be so, it is not necessary for fast skating. A sharp blade is.
Lunar Design Inc.
Palo Alto, Calif.
Minimum wage hike debate continues
In regard to Peter Mooney's Perspective [``Economist defends minimum wage hike,'' June 10, Page 17]:
When a government can set a minimum wage without regard to the limits on that same government by its people's constitution, then that same government can also set a maximum wage or a min-max anything.
It will only be limited by the ability of a talking mouth to persuade a populace of the rationality of the control in question. I haven't seen a minimum sales price set by the government; if that had been done, perhaps billions of dollars' worth of radios, TVs, etc., still would be manufactured here.
Or maybe not.
One thing is certain, aping the past Russian mistakes will not, through some magic on our part, create prosperity.
Truly, fear of a populace for its security will make it want to override the principals of a constitution.
As a wise head said, ``Give up freedom for security and you will have neither.''
Roy Cabler Jr.
Bayshore Industrial Inc.
La Porte, Texas