So far, summer has certainly been brutal in the northeastern U.S., with one heat wave following another -- the fourth to arrive this weekend. Temperatures have broken 100 degrees, and drought warnings are being posted.

Other regions of the world have suffered as well. Russia just experienced the hottest June since weather records were first kept 120 years ago. And, if expert predictions about global warming turn out to be accurate, it will only get hotter.

Heat waves like these should make us appreciate

Willis Haviland Carrier

and his invention nearly a century ago of an "apparatus for treating air" -- what's known today as the air conditioner.

More than cooling us in sizzling weather, Carrier's brainchild created an entirely new industry, best illustrated by the company that he formed,

Carrier Engineering

. Now a wholly owned subsidiary of

United Technologies

(UTX) - Get Report

, Carrier is still the world's largest manufacturer of HVAC. In 1998, the company enjoyed record sales of $6.9 billion. Its competitor,

Trane

-- a subsidiary of

American Standard

(ASD)

-- also experienced increased sales in 1998, with a 10% leap to more than $3.9 billion. Both companies give the hot 1998 summer partial credit for the increased business.

Air conditioning also has helped nurture other revolutionary products -- products like computers and jet airplanes, which couldn't operate at high temperatures without it. The invention even expanded the range where we can comfortably dwell, making the Sun Belt more habitable in summertime.

People always have desired to be in cool places on hot days. To cool off, an eighth-century Baghdad caliph supposedly packed snow -- presumably from nearby mountains -- in the double walls of his summer villa. A recent

National Geographic

article on Iran describes how Persian architects once cooled buildings and even made ice by harnessing the wind.

In the mid 1800s, New England farmers cut ice cut from frozen ponds and packed it with saw dust to preserve it in ice houses for year-round use or to send it off in the hulls of sailing vessels to the American south and the Caribbean. In 1872, a mechanical ice-making process that used an ammonia compressor was perfected for the huge King Ranch of Texas, and by 1900 it was being used in breweries and meat-packing plants.

The most noble effort to keep a person cool and comfortable occurred in 1881. An attempt to assassinate

James Garfield

had left the wounded president on his death bed in the White House. The temperature was 90 degrees and the humidity high. Naval engineers, trying to cool the room, filled a coffin-sized cast-iron box with a thousand pounds of shaved ice, salt and water. The slush from the melting ice trickled onto dozens of screens made from thin terry cloth cotton. Fans sucked outside air through the cold, sodden screens and then pumped it into the presidential bedroom. This process lessened the humidity in the air and reduced the temperature by 20 degrees. It also consumed, over the course of 58 days, more than half a million pounds of ice.

In 1902, Carrier, just a year out of Cornell University and employed as an engineer at

Buffalo Forge Company

-- now

Howden Buffalo

-- was assigned the project of reducing the humidity in the

Sackett-Wilhelms Lithograph and Publishing

plant in Brooklyn, N.Y., which printed the popular humor magazine

Judge

. Excess moisture in the summer air caused unwanted variations in the colors of the magazine's illustrations.

Carrier was the first to recognize the relationship between air temperature and its moisture content. The cooler the air was, the less its humidity. Combining the previously discovered mechanical refrigeration process with the electricity recently tamed by

Thomas Edison

, Carrier found he could reduce the moisture in the printing plant to 55%, while simultaneously cooling it to the equivalent of having used 108,000 pounds of ice a day. This was the first of a series of humidity-busting challenges presented to Carrier in paper mills, pharmaceutical plants, chocolate factories and tobacco warehouses across the United States and even abroad.

In 1915, Carrier left Buffalo Forge and, with $32,600 of capital put up by friends, formed Carrier Engineering. Replacing the ammonia compressor with the newly invented nontoxic centrifugal refrigeration system, he made air conditioning safer, more compact and efficient. Soon, he turned his efforts to cooling spots where the public gathered: hospitals, restaurants, department stores and even trains.

But his big hit, which showcased air conditioning to the average American, was with movie theaters. Typically, cinemas closed in the hot weather, but Carrier's air conditioning installed in the Rivoli Theater of New York City's fabled Broadway, changed that. People flocked there to be entertained in comfort on hot summer days. Three months of increased ticket sales that first summer paid for the entire installation, and Carrier air conditioned 300 more theaters within the next five years.

The new apparatus also caught on in Washington, D.C., which traditionally closed down in the summer. After considerable debate, the

House of Representatives

became air conditioned by the end of 1928, and the

Senate

the year after. In 1930, air conditioning was installed in the White House -- 49 years too late for poor President Garfield.

Office buildings proved more difficult to cool. Built in 1931, the Empire State Building, for example, didn't have air conditioning because the duct work needed took up too much valuable rental space. Carrier solved that problem in 1937 with the invention of the conduit weather system, which propelled cold air at higher velocity through smaller duct work.

Private homes were the last to be air conditioned. It was simply too costly: more than $1,500 in 1938 dollars. Carrier tried to market the "atmospheric cabinet" but gave up after selling only one thousand in three years. But

General Electric

(GE) - Get Report

and

Westinghouse

picked up where Carrier left off, creating a more compact, dependable system for homes that could be sold as a simple appliance rather than something that contractors had to install.

In television commercials -- at the time, a new medium of advertising -- actress Betty Furness, Westinghouse's spokesperson, appealed to American housewives by touting the health and social benefits of air-conditioned living. Demand for the appliance jumped tenfold, especially in the just-developing suburbs. General Electric stayed in the business, and today offers more than 25 different models of home air conditioners that retail between $300 and $800.

Is the market for air conditioning saturated? Has it no more worlds to make comfortable? Far from it. It should have a great future ahead. Just as it helped make the Sun Belt habitable, air conditioning can achieve the same result in other parts of the world. In fact, Carrier recently entered an alliance with Japan's

Toshiba

to bring air conditioning to global hinterlands. If Moscow, only 750 miles from the Arctic Circle, needs air conditioning -- only one-seventh of its public buildings have it -- imagine the markets closer to the tropics.

Richard B. Marrin has practiced litigation and corporate law for nearly 30 years and is a partner in New York City law firm Ford Marrin Esposito Witmeyer & Gleser. He is the author of several books and a number of articles on American history. He can be reached at

rbm68@aol.com.