Two Objects from the Science Museum's Reserve Collection (Blythe House)
Science Museum | London (Community-in-Residence)
Phil Rowley writes:
Please see my comments below on two objects I have selected from those I photographed at Blythe House - one Victorian and one 20th century : I'm planning to follow this with comments on two objects from the museum's pubic collection over the weekend.
The first object I've chosen to write about is is a Victorian device for lighting cigars which is in the Science Museum's 'small parts' store in Blythe House. The lighter stands about 18" (45 cm) high and it made of metal (gilt bronze ??), wood and ceramic and the limited information covering it said that it used hydrogen to create the ignition source. I assume that this would have been generated internally, probably by pressing a button which added a measured quantity of granulated or powdered zinc to dilute sulphuric acid, and that the hydrogen may have been ignited using a platinum foil covered with finely-divided platinum ('platinum black'). However, as a chemist, I suspect that this process would have been unreliable and I wonder how many house fires or explosions this device caused.
The second object I've chosen is an ultrasonic drill for use on materials such as glass or ceramics - Stoke-on-Trent connection ! I've never seen such a device nor even heard of one. The information on display didn't give a date of manufacture, but I would suspect that it was in the 1960 - 1970 period. Ceramics and glass are difficult to drill as they are both very hard and brittle : this machine converts electrical power into ultrasonic vibration (about 20 kHz) over very short distances (about 0.04 mm) of a metal workpiece. A mixture of fine silicon carbide abrasive and water is fed between the workpiece and the substrate and the hole is basically ground away. As there is no movement of the workpiece other than up-and-down, the machine can 'drill' any sort of hole. It seems likely that this machine was replaced when diamond-tipped tools became cheap enough to use as they could probably have achieved far higher cutting speeds, but I'd have loved the opportunity to try out a working model !