The Kerala State Science and Technology Museum had an informative exhibit on electronics on the ground level. The functional simulations did a good job of demonstrating how grid voltage modulates the thermionic current in thermionic valves, or vacuum tubes.
On display was this BEL 300 broadcast triode, with a glass envelope volume of about one litre. The model BEL 300 appears to be equivalent to the RCA 833A. With its high power handling capacity, I thought that it would make a stupendous stereo amplifier output tube. It turns out, others have already built such amplifiers.
A road roller stood near the entrance to the Kerala State Science and Technology Museum in Thiruvananthapuram. This one appeared to have been retired. I drew this sketch from memory, as I felt self-conscious about standing in public and sketching. After overcoming my hesitancy, I later went to sketch the road roller in more detail.
This road roller, made by Jessop Co Ltd, Calcutta, stood beside a road near the entrance to the Kerala State Science and Technology Museum. I believe that the neighbouring property belongs to the city’s works yard.
Most of the road rollers that I saw in Kerala were built on this pattern. I often saw crews repairing roads with these rollers. Usually a crew of workers with shovels accompanied the roller, and on bigger jobs, an asphalt mixer and a small, three-wheeled truck. I thought that these teams appeared to be easily deployable, based around one machine that could move from job to job under its own power.
On a small road, these crews seemed a good fit for the size of the job. In contrast, in my city we use huge machines that have to be delivered on flat bed trucks. No doubt, there is a payoff in reduced labour costs by using one machine that does the work of many, on infrastructure that is usually on a larger scale. However, I was reminded again how we have invested in cumbersome machines, whereas these small road-rollers, like any car, park by the side of the road when not in use.