Some heightened sensitivity to the promises of life, as if he were related to one of those intricate machines that register earthquakes ten thousand miles away.
Nick Carraway describes Gatsby with “some heightened sensitivity to the promises of life”, but then compares him to “those … machines that register earthquakes ten thousand miles away”.
Usually the promises of life would indicate that Gatsby lives life full of happiness, however, Nick then compares Gatsby to a seismometer. A seismometer is a device that delicately records the Earth for earthquakes. The earthquakes can be interpreted as a symbol for danger.
By comparing Gatsby’s sensitivity to the promises of life to a seismometer’s sensitivity to earthquakes, Nick defines the promises of life to mean the dangers in life. This reveals both Nick and Gatsby’s views and lives. Nick believes that life is full of danger and that Gatsby lives very afraid.
Here is a picture of a seismometer in case you live in a cave:
To help improve the meaning of these lyrics, visit "The Great Gatsby (Chapter I)" by F. Scott Fitzgerald and leave a comment on the lyrics box