[ 236 3 



XLIII. Tnielligence and Miscellaneous Artidiek 



On the Conversion of Starch into Sugar. 



To Mr. Tilloch. 



Sir, You will much oblige mc. by correcting a mis- 

 statement in my communication published in your Journal 

 for Au"-U5t, " On the Production of Sugar from the Starch 

 of Wlieat and of Potatoes, by the Agency of Sulphuric 

 Acid." 



Ill that paper T stated that ihe discovery had been com- 

 municated to Professor Berxelius by M. Kirchoif of St, 

 Petersburgh ; but I have since been informed by the Pro- 

 fessor, that he did not receive the communication directly 

 from that gentleman. I beg that you will excuse this trou- 

 ble, and am, sir. 



Your humble servant, 



London, Sept. 21, 1812. Wm. MoORE, 



To Mr. Tilloch. 

 Sir, — Allow me to request from you, or from dome of 

 the scientific readers of the Philosophical Magazme, an 

 answer to the following query. 



Every one knows that rauriat of silver, on exposure to 

 the sun's light, becomes in a short time of a dark hue. 

 Is there any material, solid or fluid, simple or compound,- 

 which being of a dark hue will, ou exposure to the sun's 

 light, become in a short time lighter in its tint, if not wholly 

 colourless ? 



I am, sir, vours, &c. 



'_ R. Y. S. 



SIR HUMPHRY DAW AND PROFESSOR LKSLIE. 



To Mr. Tilloch. 

 Sir, — In glancing over Davy's Elements of Chemical 

 Philosophy, I was surprised to find it alleged, that Van 

 Helmont had given a sketch of a " curious instrument, 

 verv similar to" the differential thermometer;" and a few 

 pages further on, to meet with this bottom note — " Plate I, 

 fis;? 2. represents Mr. Leslie's differential thermometer." 

 [See Plate V. fig. 5.] " Fig. 3. is copied from Van Hel- 

 mont." [Plate V. fig. 6.] " This instrument appears to 

 have been the first in^which the expansive power of heated 

 air was exhibited by its action upon cold air." On turning 



to' 



