titute of Technology (MIT). The school is investigating the technology's long-distance communication potential. In 2002, MIT's technology was used in the first "transatlantic touch," which linked researchers at MIT and University College London. The experiment involved a computer and a small robotic arm that took the place of a mouse. A user could manipulate the arm by clasping its end, which resembles a thick stylus. MIT's system creates the sensation of touch by exerting a precisely controlled force on the user's fingers. The arm, known as the PHANTOM, was invented by others at MIT in the early 1990s and is available commercially through Woburn, Massachusetts-based SensAble Technologies. The researchers modified the PHANTOM software for the transatlantic application. During the demonstration, each user saw a three-dimensional room pre- sented on a computer screen. Within the virtual room were a black box and two tiny square pointers that showed the users their position within the room. The users then used the robotic arms to collaboratively lift the box. As each user moved the arm-and therefore the pointer-to touch the box, he could "feel" the box, which had the texture of hard rubber. Together, the users attempted to pick up the box-one applying force from the left, the other from the right-and hold it as long as possible. All the while, each user could feel the other's manipulations of the box. "Touch is the most difficult aspect of virtual environments to simulate, but we have shown in our previous work with MIT that the effort is worthwhile," says Mel Slater, professor of virtual environments in UCL's Computer Science Department. "Now we are extending the benefits of touch feedback to long- distance interaction." "In addition to sound and vision, virtual reality programs could include touch as well," observes Mandayam A. Srinivasan, director of MIT's Touch Lab. "We really don't know all of the potential applications," he says. "Just like Bell didn't anticipate all of the applications for the telephone." The