â€œDear Frank,â€ writes Richard Carter of Gruts, â€œThis week’sÂ New ScientistÂ Â (20 September, 2008) contains the rather stirring story of how a lone British Antarctic Survey scientist managed to give NASA a red face by discovering the hole in the ozone layer with a 50-year-old instrument assembled in a shed. The instrument was called a Dobsonmeter.â€
The Dobsonmeter was invented by a certain Gordon Dobson, who may or may not have been related to the out of print pamphleteer whose doings are so assiduously chronicled at Hooting Yard. Judging by these excerpts from the New Scientist piece, there is a definite affinity:
Without [Joe] Farman, the truth [about the ozone layer] might not have been discovered for several years or more. But he couldn’t have done it without his trusty Dobsonmeter, first assembled in a shed outside Oxford more than 50 years earlier by another dogged researcher, Gordon Dobson from the University of Oxford‘s Clarendon Laboratoryâ€¦
The odd thing about the Dobsonmeter is that for a quarter-century it was an instrument without much use. It finally came into its own during the International Geophysical Year of 1957, when researchers decided to make global measurements of the ozone layer. They put in an order for around 50 Dobsonmeters with the London instrument maker, R. & J. Beck.
Farman remembers going to Oxford to pick up his machine from Dobson in 1956. “Even after 25 years, they hadn’t completed the instruction manual,” he recalls. “That only arrived the following year.” Farman still has his original copy. For best results, it recommends wrapping a quilt round the instrument to keep it warm.
Only about 120 Dobsonmeters were ever made, of which some 50 remain in use. Each is known by its number. Dobson’s original, No 1, is in London‘s Science Museum. Farman made his discoveries with Nos 37 and 51. Probably the oldest still in use is No 8, now 73 years old and sitting on the roof of the Norwegian Polar Institute in Svalbard. Dobson died in 1976, so he never saw his instrument’s finest hour.