is an obsolete name for very fine (less than .01 mm thick) platinum wire
clad in silver
used for electrical instruments around the turn of the 19th century. The term Wollaston wire
does not clearly distinguish the bare platinum wire from the composite silver wire with a fine platinum core.
The name refers to the person who developed the early technique for producing such fine wire.
Platinum wire was drawn through smaller and smaller dies
until it was about .003 inch in diameter. It was then embedded in the middle of a silver wire having a diameter of about one-tenth inch. This composite wire was then drawn until the silver wire had a diameter of about .002 inch. The embedded platinum wire was reduced by the same 50:1 ratio, to a final diameter of .00006 inch (1.5 μm). Removal of the silver coating with an acid
bath left the fine platinum wire as a product of the process.
Wollaston wire was used in early radio detectors
known as electrolytic detectors
. Other uses include suspension of delicate devices and sensing of temperature.
Today Wollaston wire is used in temperature sensors and sensitive electrical power measurements.
Sources include scientific suppliers
where it is extremely expensive.