"I have just begun a work in which an important part is given to a large chorus and with it I want to use several of your instruments - augmenting their range as in those I used for my Equatorial - especially in the high range"

Edgard Varese's quote is describing a new work he is creating that will involve a large chorus and a number of instruments. He is likely referring to the instruments he used for his Equatorial, which was a piece of music made up in the 1950s. Varese is recommending that he wants to use the exact same instruments for his brand-new work, but with a prolonged range, especially in the high variety. This might indicate that he wants to utilize the same instruments but with a greater pitch, or that he wishes to include extra instruments to the ensemble to increase the range of the music. Varese's quote likewise suggests that he is wanting to create a larger and more intricate sound than what he achieved with his Equatorial. By using a larger chorus and a broader range of instruments, Varese is likely wanting to produce a more vibrant and powerful noise.