This looks as if it has been extracted from the report of Major von der Marwitz, ADC to General der Infanterie Fuersten zu Hohenlohe-Ingelfingen, concerning the battle of Jena.
This is published in `1806 Das Preussische Offizierkorps und die Untersuchung der Kriegsereignisse` issued by the Grossen Generalstab by ES Mittler, Berlin 1806.
But that source does not contain the personal quotes by Sergeant N..., nor does it mention any conversation with an officer of fusiliers.