luckily or cleverly as you might imagine, within three days, they ran over a huge debris field. you remember, titanic, of course, was huge. so there was a lot of stuff on the sea floor. and ultimately, on the third 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 discovery, 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 the ocean's much more transparent to sound. and can you see with light. i mean, with an optical system, you're only seeing sort of half