BAIRD &T&TLOCK (LONDON) LTD. 



4096 



4096 5 Thermometers, Standard " E," of Jena glass, but in four thermometers covering from o to 400 C., 

 the last three instruments being filled with nitrogen gas and provided with zero point graduations. 

 Length, 18 in., subdivided in . t 



No. i 2 34 (Borosilicate glass) 



Range -5 to 105 C. 95 to 205 C. 195 to 305 C. 295 to 405 C. 



Price 150 1 12 1 14 1 18 



The above set complete in morocco case, 612 6. 



4 



10 

 14/6 



If required with National Physical Laboratory Certificate, the extra cost will be- 

 No. ... .. .. .. .. i 2 3 



N.P.L. Certificate every . . . . . . 10 10 10 



Price .. .. .. .. .. 7/6 10/6 14/6 



Price complete with Certificates, 8 19 6. 



The sets quoted can be supplied graduated in Fahrenheit scale in i and i corresponding to the Centigrade 

 4 and |, at the same prices, and can also be supplied graduated in F. and -j^" C. at extra charge in proportion. 



NOTE RE THERMOMETERS WITH ZERO POINT GRADUATIONS. 



At normal temperatures the enlargement in the bore is partly filled wiUi mercury. Should small particles 

 become separated in transit or handling, as sometimes occur, the thermometer should be carefully heated till the 

 mercury re-unites, which it will readily do provided the separated particle of mercury has not closed the upper 

 end of the enlargement against the passage of the enclosed nitrogen gas. In such case the mercury must first be 

 dislodged by tapping the bulb or by using greater heat to cause the mercury to unite in the chamber at the top 

 end of the bore. 



If preferred, these thermometers can be provided with graduations at about 15 or 20 C. instead of at o, 

 by this means the mercury at normal temperature is in the capillary below the enlargement, and the risk of separa- 

 tion reduced to a minimum. 



When heating the bulb of Standard Thermometers the precaution should always be taken to place the bulb inside 

 a small test tube to avoid contact with the flame. 



4097 s Thermometers, Standard " F," of Jena normal glass, nitrogen filled, and annealed to avoid any 

 serious change of zero, length about 12 in. The thermometers are good quality, and would pass the 

 National Physical Laboratory, but are not of the standard accuracy of Thermometer Standards A to E. 



Range 



Or 



Price 



Extra cost of N.P.L. Certificate 

 at every 50 C. or 100 F. . . 



o to 200 C. in i 



30 to 400 F. in i 



IB/. 



o to 250 C. in i 



30 to 500 F. in 2 



15/- 



61- 



o to 300 C. in i 



30 to 600 F. in 2 



I8/- 



91- 



771 



