Dear Mr. Wells,
I am writing to thank you for hooking me up with that now mutual friend of ours. My shipment of Cavorite arrived in the Port today. Rest assured I have it properly shielded and safely secured under The Gangplank Pub in the densely populated Clockhaven district of New Babbage. It should be safe there.
By the way, I understand you have not yet documented the existence of this wonderful substance, and it may be years in fact before you see fit to do so, so I assure you sir, as a fellow amateur scientist and like-minded professional adventurer, I will maintain discretion in the name of brotherhood. If there is one person you can trust with a secret it is Emerson Lighthouse.
Dr. Emerson Lighthouse.
PS: Do you mind if I call you Herbert?