I want to know the answer to the following question:
The Volta lab improved the phonograph by replacing tinfoil with what substance?
All the background I'm provided with is that "The Volta Laboratory became an experimental facility devoted to scientific discovery, and the very next year it improved Edison's phonograph by substituting wax for tinfoil as the recording medium and incising the recording rather than indenting it, key upgrades that Edison himself later adopted.". Is that enough to answer the question?