Last seen in:
Related Clues:
- (Of radiation) with a longer wavelength than light
- Having longer than visible wavelength
- With a frequency between the red end of the visible spectrum and microwaves
- For both eyes
- Up north, father finds a revolutionary colour you don¿t normally see
- Find out about unusual end of spectrum
- Governing, managed to conceal source of riches — it's invisible
- Find out about unusual forms sensitive to some radiation
- Poem on strange duke's taken in new light
- Hot objects radiate this
- Unusually rare find that's not normally visible
- Type of radiation just outside visible range
- Radiation popular chap revealed around Burlington House
- Radiation from heated objects
- Find out about unusual part of spectrum