248 



HENDRY, ON THE SACCHARO-POLARISCOPE. 



generation that Kiitzing himself made the alteration before 

 Smith published his ' Synopsis/ although Smith was unaware 

 of it. To this species must be referred Stephanodiscus 

 Niagara of Ehrenberg, and perhaps also his S. Egyptiacus. 



The Saccharo-Polariscope. 

 By William Hendry, Esq., Surgeon, Hull. 



The instruments usually figured as employed in the po- 

 larization of saccharine solutions are, for the most part, of 

 costly and complex character. Having experienced a 

 little curiosity in the subject, induced through a desire 

 to investigate diabetic urine microscopically, I had occa- 

 sion to refer to an article contained in ' Morfit's Chemical 

 Manipulations/ and, in pursuance of the methods therein 

 described of Professor M'Culloch, Soleil, Clerget, and others, 

 I have been enabled to fit up 

 an apparatus which will be found 

 efficient, convenient, and inex- 

 pensive, whereby the beauteous 

 phenomena of right- and left- 

 handed polarization indicative 

 of cane or grape sugar may be 

 readily exhibited, or the arcs of 

 prismatic coloration measured, 

 as occasion may require. 



I am indebted to Mr. Row- 

 ney, of Hull, for the accom- 

 panying drawing, representing 

 the arrangement of the appa- 

 ratus. 



First, procure a gutta-percha 

 tube a, of a calibre to receive 

 the ordinary b eye-piece (which 

 might be in demand for other 

 uses), and about 10 inches in 

 length ; fix upon its lower or 

 distal extremity a disc of clear 

 glass between two layers of 

 gutta pcrcha cemented by heat, and perforated to transmit 

 the polarized beam of light, the polarizer », as usual, being 



