But Mr. Gough refused, he was busy with his new invention: an electrophone.
但高夫先生拒绝了，他正忙乎他的新发时：电子乐器。
英语百科
Electrophone
The electrophone category was added to the Hornbostel-Sachs musical instrument classification system by Sachs in 1940, to describe instruments involving electricity. Sachs divided his 5th category into 3 subcategories:
The last category includes instruments such as theremins or synthesizers, which he called radioelectric instruments.