C6 NEGEETTI AND ZAMBEA, HOLBOEN YIADUCT, B.C. 



NEGRETTI & ZAMBRA'S 

 PATENT IMPROVED-FRAME STANDARD DEEP-SEA THERMOMETER. 



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FIG. l. 



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FIG. 2. 



82. NEGRETTI & ZAMBRA'S Improved Standard Deep-sea Thermometer has been abundantly 

 proved to be the only thermometer that ought to be used in researches into the temperature 

 of the sea below the surface. It is quite applicable for testing the temperature of the sur- 

 face water, but merely for this purpose a less expensive instrument would usually be 

 employed. For taking temperatures at moderate depths, from a few feet to a few hundred 

 fathoms, NEGRETTI AND ZAMBRA'S Wooden Float form amply suffices and is quite suitable. 

 The only objection that has been raised to this wooden float is, that in sounding to great 

 depths a check upon the line, caused by the motion of the ship due to the heave of the sea, 

 may make it turn over and register, so that the temperature at the desired depth is not 

 obtained. In very deep soundings it is often desirable to have a series of thermometers 



