G. Turner, Scientific Instruments, 1998, has a paragraph on dipleidoscopes. Invented by James Bloxam, patent 9793, 20 June 1843, marketed by Edward Dent, a clockmaker. Used for timing meridian passage of the sun, accurate to a few seconds. It was a simple device, a hollow 90 degree prism, 2 sides silvered. At meridian, two images of the sun - one from glass side, one reflected off both mirrors - would coincide.
Now a request. I understand that the central patent library in England has moved (?), and that access to these records has changed. Can anyone tell me how someone overseas can order the full text of a British patent? Do they go back to the 1700s? thanks, Peter _______________________________________ Peter Abrahams [EMAIL PROTECTED]
