MEMORANDA. 



109 



nut E the disc B, and with it the thin glass cover, may be 

 removed for the purpose of cleaning, or for attaching a fresh 



cover in the case of breakage. 



On moving the disc and cover 



riG .1 



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aside, as shown in fig. 1, the object, with a sufficient supply 

 of water, can be readily introduced ; some care, however, is 

 required in doing this, but dexterous management of the 

 dipping tube will suffice to disperse all air-bubbles. — Thomas 

 CuRTBis, F.R.M.S. 



