29 OCTOBER 1927, Page 14

Everyone who cares for birds should share the interest of

inventors in the prize of £100, offered by the Royal Society for the Protection of Birds, to anyone who shall find an efficient substitute for the caged bird as an agent for detecting poisoned air—generally carbon-monoxide—in mines. Accord- ing to present custom, canaries, linnets, redpolls, and doubtless other sorts of small birds are used. That high-strung air- and freedom-loving creature, the bird, is quite peculiarly sensitive to the poisons that are characteristic of stuffy places ; and it has been noted that the longer birds have been kept in rooms the less sensitive they are for the purpose. The natural bird has need of the free air. It should not be difficult in this chemical and physical age to discover a something that should, -detect -foulness and proclaim it- even more certainly

than the small bird. It used to be said that man would never weave a thread as finely perfect as the silk of the geometric spider ; and it was used until the other day almost by astronomers who needed to quarter the telescope with extreme accuracy. We can excel the spider in this regard. It should be easier to supplar.t the bird.