day, i believe, they ran over a 20-foot boiler. and they had a book and sort of a famous scene where they looked it up. so the sonar was involved in the search for "titanic." but the actual sdoidiscovery, i think, was purely optical. it's a wonderful story. and -- and very, very luckily for ballard, he found it. >> you said purely optical? >> yes, sir. >> so then, do you think any sort of optical equipment would be better for the search for flight 370? >> well, not really because we all imagined that the sonar would find those contacts. and if you think about the amount of area that you can see with sound, which is much more -- ocean's much more transparent to sound, and you can see with light, i mean, with an optical system, you're only seeing sort of half a basketball court or a quarter of a basketball court. but with the sonar, it maps two beams, one to each side.