Mono Monday, 19th century inventions

Not the chainsaw itself, even though its origins go back to 1830, but the later invention that made it viable as a hand held device for cutting timber - the 2 stroke engine.

The 2 stroke engine was invented by Dugald Clerk, a Glaswegian Engineer, and patented in 1877, followed by a later (more developed) patent No.1086 of 1881. The patents are important in British history as Dugald Clerk went on to become a founding partner, along with Baron Edward Marks who invented the funicular railway, in the London based  Patent Agent firm Marks and Clerk which has survived to this day as one of the largest and most successful global firms of Patent Attorneys.

In my 42 year career as a Mechanical Engineer and Patent Attorney, firstly in New Zealand and then in Australia, I was a partner for some time in an Australian patent firm closely associated with Marks and Clerk, where I was fortunate to discover the amazing work of Dugald Clerk in the 1800s.

The 2 stroke engine has progressively fallen out of favour for outboard motors, motorcycles and lawnmowers, because it is inherently more polluting and less fuel efficient than the 4 stroke engine, but is still extensively used in situations calling for a high power to weight ratio, such as chain saws and leaf blowers. In the not too distant future these will all be replaced with electric motors and powerful lightweight battery packs.

The extra shows a drawing of Dugald Clerk's patent two-stroke gas engine of 1881.