Complex sentence: It consisted of a, graphite cylinder lying on its side, penetrated through its entire length horizontally by 2,004 aluminum tubes containing two hundred tons of uranium slugs approximately diameter long and sealed in aluminum cans went into the tubes.
Split into simpler sentences: It consisted of a, graphite cylinder lying on its side, penetrated through its entire length horizontally by 2,004 aluminum tubes containing two hundred tons of uranium slugs. Approximately diameter long and sealed in aluminum cans went into the tubes.