Intelligence and Miscellaneous Articles. 315 



for each 1 00 parts of potatoe starch is sufficient, if the heal ap- 

 plied be a few degrees above 212° Fahr.; and also that then two or 

 three hours are sufficient to give crystallizeable sugar. He applies 

 heat in wooden vessels by means of steam. — Quarterly Journal, 

 June 1829. 



AMMONITES IN CALCEDONY, FROM HAYTOR ? 

 We have received from Mr. Shirley Woolmer, of Exeter, two com- 

 munications respecting the occurrence of ammonites in calcedony 

 from Haytor. In one specimen, bearing also crystals of quartz 

 and haytorite (some of the latter of a crimson hue), and " red blis- 

 tered manganese" is stated to be " a yellow ammonite of one-fourth 

 of an inch in diameter, with three circumvolutions ;" also "six am- 

 monites of two circumvolutions, three of which are very discernible 

 with a glass ; the others are rather obliterated." Besides these, in a 

 small round cell Is " a black ammonite, with two circumvolutions." 

 Mr. Woolmer observes, that " the external character is that of the 

 Cornu Ammonis, with evident whirls and ridges ; similar ones were 

 discovered by Harenberg in Germany, hardly perceptible except with 

 a glass ; they are very abundant in many specimens I have of Haytor 

 calcedony. I extracted several of them, but they were so brittle 

 that they crumbled to pieces on my attempting to try an experiment 

 upon them : the nearest approach to them is in the 3rd volume of 

 Parkinson's Organic Remains, plate xi. fig. 26, 27, 28. These 

 figures are more distinct, but of the same character." 



ACTION OF MURIATIC AND SULPHURIC ACID UPON HYDRO- 

 CYANIC ACID. 



M. Kuhlman states that he has sometimes preserved hydrocyanic 

 acid, prepared according to M. Gay-Lussac's process, for some 

 years without alteration, whilst at other times it has decomposed 

 within a week of its preparation. To determine the causes which 

 accelerate or retard this decomposition, the action of muriatic acid 

 was tried upon the hydrocyanic. 



When these acids were mixed, the bottle which contained the 

 mixture was sprinkled with fine cubic golden yellow-coloured cry- 

 stals in twelve hours ; some of the crystals were hopper-shaped, like 

 common salt. Several of the crystals were less deeply coloured, and 

 those which were precipitated by longer contact were quite colour- 

 less. The liquor retained its limpidness, and was diminished nearly 

 to one half by the formation of the crystals. 



The experiment was repeated by mixing equal quantities of the 

 two acids, the hydrocyanic acid being recently prepared. No yellow 

 crystals were obtained, probably on account of the excess of muriatic 

 acid J but a great quantity of colourless crystals was obtained, 

 which resembled those |)rocurcd towards the end of the former ope- 

 ration. 



These white crystals were heated in a glass tube, and converted 

 into a white vapour, which condcn.sed in a powdery form ; potasli and 

 lime separated ammonia from them, thev were very soluble in water, 



2 S 2 and 



