4f5S DistrilnUion of the Atmosphere, 



for a short time ; but the effect the quantity had upon the 

 fourth yard was very plain indeed, turning it quite yellow in 

 about ten days after it was put on. It was not sufficiently 

 powerful to kill either the moss or grass, which continued in 

 that sickly state till the autumn, when it recovered ; and at this 

 moment I cannot perceive the slightest difference in the ap- 

 pearance of all the four yards. From the above experiments, 

 which are certainly on a very limited scale, it would not be- 

 come me to give a decisive judgment on the merits of salt as a 

 manure, or stimulant ; yet they are sufficient, with what I hear 

 generally, to give me but an indifferent opinion of its useful- 

 ness, as applied to the above objects. I have used it success- 

 fully, put on in a large quantity, in destroying weeds on 

 approach roads ; but it must be done annually, to have the 

 effect of keeping such constantly clean. I would not recom- 

 mend its being laid on garden walks for that purpose, as I 

 lately witnessed the box edgings of a garden completely de- 

 stroyed by it. In paved courts, or stable yards, it might be 

 used successfully in destroying the grass, weeds, &c. ; and, 

 being now so cheap an article, it would be a considerable sav- 

 ing, compared with hand-weeding. In short, I have a higher 

 opinion of its destructive qualities than its vivifying properties, 

 at least as far as I have seen it applied. I am. Sir, &c. 



W. M'MURTRIE. 



Shiigborough Gardens^ Nov, 20. 1827. 



Art. V. A brief Essay on the Atmosphere, sho'wing the Eco- 

 nomy of Nature, in the Distribution of it, for the Support of 

 Animal and Vegetable Life. By Mr. P. Masey, Jun. 



Atmospheric air is composed of gaseous fluids, in the pro- 

 portion (in round numbers) of 21 parts oxygen, 78 parts 

 nitrogen, and 1 part carbon, hydrogen, and carburetted hy- 

 drogen, in every 100 measures. 



Oxygen is the vivifying, or vital principle ; it has the natu- 

 ral property of accelerating the circulation of the animal fluids, 

 and must be regarded as absolutely necessary for the support 

 of life, as this cannot exist without it. Yet oxygen must only 

 be inhaled in the proportion nature has provided ; for, if the 

 proportion of oxygen and nitrogen were reversed in the air, 

 the circulation of the fluids would be so stimulated, as to be 

 totally destroyed by over-excitement. If a person were to 

 breathe pure oxygen but a few minutes, the impetus to the 

 pulse would double its action, and destroy that life which, in 



