On the idiosyncratic interpretation of the action of what Draper called "Tithonic rays" see Hentschel (2002). Hentschel, Klaus (2002). "Why not one more Imponderable?: John William Draper and his `Tithonic rays'". Foundations of Chemistry. 4 (1): 5–59. doi:10.1023/A:1014443008465.