1906 Mietz and Weiss 6hp
1926 Hatz R-5 (5hp)
There are still some ancient boats operating with hot-bulb engines, and I have seen that some NGOs were supporting the usage of this kind of engine for stationary applications in remote and underdeveloped areas in Africa and Southeast Asia.
An advantage of this layout is that it doesn't require neither an electric ignition or a pilot-injection to operate with pure gaseous fuels (including biomethane from a biodigester installed in a farm), plus they have a great adaptability to many vegetable-based fuels and even animal fats.