RAIRD &TATLOCK (LONDON) LTD. 



3874 



3872 



3873 



3875 



3872 Nicol's Specific Gravity Tube. Capacity about 5 c.c. 



each 



10 c.c. 



3873 The Pollard Regulator 



This simple device is for maintaining a normal temperature in a given liquid for several hours, and is 

 primarily intended for taking accurate gravities with a Westphal or chemical balance, or for determining 

 solubilities at standard temperature. The outer vessel contains a specially prepared Acetic Acid with melting 

 point exactly 60 F. ; the latent heat of which is used for maintaining the tetnperature. 



DIRECTIONS. 



During the winter months the acid will be frozen ; it must be melted, or nearly so, before the apparatus is 

 used. During the subsequent regelation, energy is given out to maintain a normal temperature for hours. 

 Thus the "capacity" of the instrument is about sixty "degree-hours." Supposing the laboratory tempera- 

 ture be 50 F., the liquid in the inner tube will be maintained at 60 for six hours, during which time many 

 gravities can be taken. 



During the time the atmospheric temperature is above 6o g F., the use of cooled water is necessary to 

 freeze the acid, and the "capacity" of the apparatus is necessarily lessened. The temperature is so accurately 

 regulated that no thermometer is necessary. 



CATjTION. Superfusion must be avoided by shaking, or by the cooling of some part of the apparatus 

 with a few drops of ether. 



3874 Spoons, iron small 



3875 Spoons, heavy glass 



. . per doz. 

 . . each, teaspoons, 6d. ; tablespoons 





 1 



Price 5 



1 

 1 



3876 



3876 Spoons, horn. 



Length 

 Price 



,, . . 



3877 Spoons, horn, with spatula ends. 



Length 

 Price 



4 



4d. 

 3/6 



5 

 5d. 



4/6 



3877 



6 

 6d. 



5/6 



7 

 6d. 



5/6 



8 in. 

 lOd. each. 

 9/6 per doz. , 



8J in. 

 lid. each. 

 10 /- per doz. 



CROSS STREET HATTCflST GARDE1ST, E-C 



732 



