1835.] 



Scientific Intelligence. 



319 



The thin portion of the mud afforded no ammonia Ly caustic 

 potash. The filtered liquid was brown. A drop of it placed on 

 silver produced a black mark of sulphuret of silver. An acid 

 dropped into this liquid occasioned the disengagement of sulphur- 

 retted hydrogen, and a yellow fl.ocky precipitation of animal matter. 

 When well washed it acted on turnsol paper, and saturated alkalies. 



Caustic ammonia takes up a brown matter, soluble in cold water, 

 and reddening turnsol. The] same substance, precipitated from its 

 alkaline solution by an acid, is scarcely soluble in cold water, although 

 it communicates to it a brownish colour. 



By distillation much empyreumatic oil is obtained, as well as am- 

 monia and sulphur, while charcoal remains, which, after combustion, 

 leaves a quantity of oxide of iron. — Ann, de Chim. 1. 213. 



Ylll.— Gums. 



Herberger has obtained different results from Guerin. He finds that 



1. Gum arable is not quite identical with gum Senegal, neither 

 with regard to its chemical or physical properties. » 



2. Gum Senegal differs from gum arable in its external appear- 

 ance, in having a higher sp. gr. Gum Senegal forms, with water, a 

 jelly, more sensible to the salts of oxide of iron than gum arable. 



200 grs. of each of these gums were exposed to a temperature of 

 34o R. (108 J F.) until they ceased to lose weight. 

 Gum arable lost in half an Gum Senegal lost in half an 



hour - - - 11 grs. hour - - - 11 grs. 



The second half hour 2 5 



The third - - 2 4 



The fourth - - 2 ... 1 



17 21 



100 grs. exposed to a temperature of -\- 80 R. lost — Gum arable 

 17i; gum Senegal 19| ; but underwent a slight decomposition. 

 The specific gravity in three experiments was — 



Gum arable. Gum Senegal. 



1st. 1-5256 1-6510 



2d. 1-4606 1-6511 



3d. 1-5103 1-5686 



Solubility. It is difficult to determine this point. Herberger 

 fixes upon that state in which it can just be poured in drops. 



Gum Arabic. Gum Senegal. 



A 4- l2oR(59°F ) equal parts of dried 72 parts dried gum at 34o R in 



gum and distilled water. 

 A -f 80« R (2120F) 108 parts of gum 

 in 100 parts of watei;. 

 The capacity of gum arable in enveloping the oils is to that of 

 gum Senegal as 382 to 964, or as 19 to 32. 

 Chemical Reaction, 



100 parts distilled water. 

 96 gum in 108 parts water. 



R-eagents. 



Paper of blue turnsol. 

 Protonitrate & pernitrate 



of mercury. 

 Subacetate of lead. 

 Solution of iodine. 

 Silicate of potash. 

 Subborate of soda. 

 Salts of oxide of iron. 

 (Jourde Pharm. xx. 

 40 



1 ^um arahic in 

 20 water 



Red 



Whitish muddiness 

 White chesey precp. 



White flocky precp 



Red colour produced 

 after slight mud- 

 diness 



I 1 part frum Sene- 

 gal in 20 water. 



Red 



The same 



The same 



Immediate pro- 

 duction of an 

 ochre jelly 



