Clark. — Harvard Deep-Sea Thermograph. 



PLATE 1. 



Fig. 1 . Thermograph ready for insertion in protective steel shell. 

 Fig. 2. Clockwork and \dew of interior of the rear casting. 

 Fig. 3. Section showing the optical sj'stem, u-v-c, and related parts. 

 Uniform scale: 47 per cent of natural size. 



