As the Great War drew to a close, Dr Throg decided to capitalise on his outstanding military success by creating a new, multi-purpose vehicle. His “Amphi-trac” was intended to combine the towing abilities of a traction engine with the hydrodynamic qualities of a steam yacht. The machine was fitted with full-time four wheel drive, plus twin screws for water travel. Dr Throg had retained his preference for a wood burning boiler, regarding coal as merely a degraded form of wood and unworthy of consideration. He had also, with an eye for potential military use, made the Amphi-trac’s hull and running gear of armour plate.
This did make the Amphi-trac rather cumbersome, but he felt that the added safety more than justified the extra weight. In mid-July 1919 Dr Throg successfully concluded his tests of the vehicle’s cross-country abilities, and made his way to the local beach. He carefully chose a gentle gradient to the water’s edge, selected Forward gear and Screw Drive, and steamed boldly into the surf.
At this point the front wheels of the vehicle entered a large patch of quicksand. With the small front wheels passing sand to the rear wheels, which in turn passed the sand to the screws, the vehicle rapidly proceeded to bury itself . As the bow plunged into the water, Dr Throg realised all was lost and hurled himself over the side. All may have ended badly for the good Doctor, but he was fortunately rescued by a passing group of beach fishermen, whose massive rods and reels soon winched him to safety.
The Amphi-trac was lost from sight within seven minutes and thirty seconds; the only sign of its passing being a small fountain of damp sand. Some say that the rusting remains of its smokestack may still occasionally be glimpsed at low tide.
Dr Throg returned home in a pensive mood. It would not be true to say that he doubted himself or the potential of steam power. In his opinion, the combination of genius and high pressure steam would eventually win out. On the other hand, these large scale efforts did tend to have ruinous effects on the bank balance. After a period of contemplation, the Doctor came up with a solution – he invented a small, efficient, steam-powered contraceptive device.
His device was, admittedly, expensive. But when sold “under the counter” Dr Throg’s Patent Preventative found great favour amongst a certain class of people, and this success soon allowed the good Doctor and his long-suffering wife Florissa (nee Butthocks) to retire in a modest degree of comfort. Dr Harold spent the rest of his days collecting and breeding his colourful tropical ferrets, while his nights were spent in the company of his wife “Flossie”. Together they spent their twilight years frequenting the local nightclubs, where many of their 17 children played in the family jazz band, the internationally renowned “Throg’s Sprogs”.