Not many people would want Walter's job. As a test subject for new clothing, he is subjected to harsh conditions that simulate extreme environments such as wind blown mountaintops or Arctic tundra. But Walter is no ordinary employee. He is the first mannequin of his kind that is capable of walking, dressingand sweatinglike a real person. Described in the July issue of the journal Measurement Science and Technology, Walter should help scientists design apparel better suited to settings in which, as the researchers put it, "thermal comfort may be a matter of life or death."

The U.S. Army started developing mannequins for testing the limitations of their uniforms as early as 1940. Over the years the dummies became more lifelike, but one aspect of human physiology continued to prove elusive: perspiration. Now Jintu Fan and Yisong Chen of the Institute of Textiles and Clothing at Hong Kong Polytechnic University in Kowloon have developed a skin for Walter that simulates sweating. Tiny pores in the fabric covering permit the evaporation of "sweat" by transferring moisture from heated water inside the mannequin. Thanks to a convenient zipper down Walter's back, different versions of the skin can be interchanged to mimic varying rates of perspiration.

Limitations to Walter's lifelike qualities remain, however. For one, he perspires uniformly over the entire surface area of his body, in contrast to the distribution of sweat in a real person. Still, Fan says "The mannequin will also be extremely useful for better understanding the dynamics of heat and moisture transfer from the human body to the environment." Pretty smart for a dummy.