1820.] Scientific Intelligence. 307 



5. Mr. Dalton, in his iogenious " Meteorological Observations and Essays," 

 has proved the actual existence of beams of magnetic matter in the atmosphere, 

 having directions corresponding to those of the tlipping needle, which that author 

 supposes to be guided by the earth's magnetism. Inslead of this, may vee not rather 

 consider them as constituting the great directive agent, and that they give rise to 

 those magnetic phenomena hitherto attributed to the earth's magnetism, instead of 

 being guided by it ? This view of the subject would be very consistent witli the 

 ideas of Mr. (Dhristie, as given in the commencement of this section. 



Article X. 



SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS 

 CONNECTED WITH SCIENCE. 



I. Yeast as a Manure. 



A very curious experiment was made in the early part of this 

 summer by my friend Mr. Philip Taylor, of Bromley, the effects 

 of which I had an opportunity of witnessing in the month of June. 

 It deserves, I think, to be generally known, as various cases may 

 occur in which it may be employed with advantage. He put 

 upon a part of a grass field which surrounds his house at Brom- 

 ley a quantity of common porter yeast, in order to see what effect 

 it would have as a manure. In the month of June, when I saw 

 the field, the effect of the yeast was very remarkable. That por- 

 tion of the field which had been manured with it was of a much 

 darker colour, and the grass on it was much longer than on the 

 remaining portion of the field. Thus there cannot be a doubt 

 that porter yeast, and probably every kind of yeast, may be 

 employed as a very efficacious manure. It is easy to imagine 

 various cases in which such yeast might be applied as a manure 

 with considerable advantage. 



II. Yeast. 



Chemists have not yet been able to satisfy themselves of the 

 chemical nature of yeast ; nor have they come to a definite con- 

 clusion with respect to the part of the very complex body com- 

 monly called yeast, which really acts as a ferment. Indeed the 

 experiments of Kirchoff seem to lead to the conclusion that yeast 

 owes its efficacy to gluten and starch acting upon each other, 

 and that both of these bodies must be present in yeast (probably 

 in some pecuhar state) before it be capable of exciting fermen- 

 tation. That pure gluten alone does not answer as a ferment 

 has been long known ; yet any person may easily satisfy himself 

 that gluten constitutes a very considerable portion of common porter 

 yeast. It was customary some years ago to reduce porter yeast 

 to dryness, and in that state it was carried to the West Indies, 

 and probably to other places, where it was brought by means of 

 water to its original state, or as near it as possible, and then 

 .employed as a ferment. Now when yeast is dried, it acquires 



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