PALO ALTO, Calif. - Wouldn't you like to sample a chicken entree before making dinner reservations, simply by visiting a restaurant's Web site?

How about stroking the cashmere sweater you're thinking of purchasing online?

People are pretty much limited to seeing and hearing things over the Internet these days. But efforts are under way to make the Internet moresensory - by adding touch, taste and smell. It's no joke, but skepticism is understandable.

After all, it wasn't too long ago that computers could display littlemore than text. At the time, researchers had difficulty explaining thatthe machines would evolve to eventually show movies and play music.

"Our largest challenge is trying to convince people that this is indeed possible," said Bruce M. Schena, chief technical officer for Immersion Corp. "It seems like a lot of science fiction to a lot of people."

Some of the rudimentary capabilities are available today. Others are expected in the next year or two - and beyond.

Late last year, for instance, Logitech began selling iFeel computer mice,using touch technology from San Jose-based Immersion.

The devices produce bumps as you run across icons on the desktop, and Websites can program them to vibrate with the contours of a photographed sweater.

Immersion is also working with researchers at Stanford University in Palo Alto and the University of Wisconsin at LaCrosse to develop surgical simulation for medical students.

Using scissorlike handles attached to virtual forceps, you can feel tension as you pull computer-generated skin, and a hard knock as you hitbone.

The technology could help students learn and practice advanced procedureswith top-rated surgeons from far away. Doctors could prepare forcomplicated procedures by first simulating them using a real patient's attributes.

Meanwhile, Trisenx Inc. of Savannah, Ga., is developing a device to"print" flavors on a potato wafer. The computer peripheral, due out byearly next year, would allow you to sample a chocolate cake you see at a Web site by spraying chemicals that mimic the cake's smell and taste.

Trisenx already has a separate smell-only device, released in December, with 20 fragrances.

AromaJet.com of Plano, Texas, has an Internet-based kiosk for perfume stores in the works, while DigiScents of Oakland, Calif., is developing smell attachments for computers.

The DigiScents units could blow pleasant scents, such as fruit, along with foul ones like burning rubber. Those attributes have earned the speakerlike iSmell units the nickname "reeker."

How do they work?

The smell and taste devices come with basic chemicals that are combined in various proportions, using "recipes" from a Web site. It's similar tohow computers combine the primary colors of red, blue and yellow torepresent varying hues.

For touch, sites tell haptic devices such as the iFeel mice when and how to vibrate.

Bringing these senses to the Internet permits new forms of communications, for the blind, as well as the sighted.

Novint Technologies Inc. in Albuquerque, N.M., is developing a three- dimensional Web browser to navigate touch-sensitive environments.

"You can walk into a [virtual] store and actually push around a shopping cart," said Tom Anderson, Novint's chief executive. "With things like jewelry, if you just see a picture, you don't know if you want to buy it. With this, I could turn it around and see it sparkle and feel its weight."

One could use a smell device to add rose scents to an online card for Valentine's Day, or to help schoolchildren smell a foreign land during a geography lesson. Game developers, meanwhile, are looking to add touch and smell to action and fantasy games.

Beyond the Internet and computers, how about scent-enabled movies? "We use musical scores to create mood, to manipulate your emotion," said Joel Lloyd Bellenson, cofounder and chief executive of DigiScents. "Scent will have the real thing. You can feel anticipation, exhilaration and arousal."

Or what about television? With a new round of Survivor about to debut on CBS, notes Trisenx marketing director Kathey Porter, "wouldn't it be great if you could smell the Australian Outback?"

Years from now, scent "cameras" may even compliment personal Webcams or video recorders. Devices that can analyze and reproduce the chemical composition of smells are costly, cumbersome and limited to scientists now. But DigiScents is trying to develop a consumer version.

The technology still needs work.

For now, online "touching" is akin to touching an object with a pen or a stick. Reproducing the sensation felt by fingertips is still years away.

"Generally speaking," noted Ralph Hollis, a principal research scientist at Carnegie Mellon University in Pittsburgh, "people are not completely fooled yet."

Then there's delay, the fraction of a second it takes light - your data -> to travel through the Net. For truly interactive applications, such as virtual surgery, those milliseconds can be crucial. It's those first few milliseconds that tell your brain what you are hitting, and even the shortest delay can be deadly.

The smell devices, meanwhile, are limited to the chemicals that come with them. You may be able to reproduce a pepperoni pizza, but not the one from Pizza Hut. You may get a basic rose scent, but not the traces of other fragrances that accompany roses in nature.

Plus, scientists do not know all the basic ingredients of scent. The human body has hundreds of smell receptors, and some may work in combination to recognize thousands of odors.

Pam Dalton, a research scientist at the nonprofit Monell Chemical Senses Center in Philadelphia, believes that once those odors are cataloged and reproduced, "the potential is limitless."

But even then, will computer users really want to eat something from a printer-like device, or inhale artificial fragrances?

Or in the case of a glove that might one day reproduce the sensation of fingers, will people want to share the device with a sweaty coworker?

And will people even want computers to invade their lives - by manipulating sensations - in yet another way?

Proponents believe so and expect the devices to be as common as audio speakers once they overcome the social hurdles.

"It's not different from when sound was first added to the computer," said Porter of Trisenx. "People said, 'We don't need to hear our computers talking all day. It's just some additional chatter and noise.'"

Soon, she said, people will wonder how they got by with only sight and sound. "They will feel like the Internet experience is not complete unless they have this."

On the Web:

http://www.monell.org
http://biocomp.stanford.edu
http://digiscents.com
http://trisenx.com
http://aromajet.com
http://immersion.com
http://novint.com