Nearly every person is aware that a watch without a regulator would be of very little use ; sometimes it would be too fast, and at others too slow, and although it would go, it would not keep time. Those who have seen a steam engine may have noticed a part of it shaped thus, j, with two balls twirling round on the end of it—this is the regulator. The power of steam was known long before Watt's great invention, but there was no method of regulating it ; for sometimes it would whirl like a mill, and at others it would go as slowly as the pendulum of a large clock. Hence wc clearly see the value of a mechanical regulator, and from it we can judge by analogy of the utility of a chemical regulator —such is nitrogen. The ethereal fluid surrounding the earth, which we call air, is the source of a terrific power—oxygen ; and were it not for the regulator (nitrogen) tliat is mixed with it, all the operations of nature which are dependent upon the air would go at a velocity so frightful as to defy description. If a candle were lighted, it would instantly be burned out ; if a fire were lighted in a grate, not only the fuel, but the whole iron range, bars, trivet, and all, would be consumed. Life, instead of extending to threescore years and ten, would probably terminate in a week. We can thus perceive how much we are indebted to the Divine controller of the universe, who, in giving the air the power (oxygen) gavewithit also its regulator (nitrogen). The air contains four parts of nitrogen to one of oxygen : so that when we breathe, we inspire nitrogen in much greater proportion than we do oxygen ; yet, singular enough, this gas, nitrogen, has no direct action upon our lives ; it is perfectly inert ; and it is this singular quality of nitrogen which renders it so very remarkable. Chemists cannot, by any straightforward process, make it unite with any other substance. It is a perfect "bachelor" or "old maid" among the elements. Nevertheless, it does succumb to some of nature's laws, for when the lightning flashes through the sky, we find nitrogen united with hydrogen. A salt of ammonia is then produced ; this, the rain brings to the earth; plants absorb it, and animals eat thereof. Finally, we find nitrogen as one of the constituents of animal tissue. True, however, to its character, nitrogen, the moment it has ceased to be under the influence of the vital principle, endeavors, as it were, to again become free. The most unstable, the most explosive and dangerous compounds, are those containing nitrogen. Chemists produce certain materials, which, by the slightest blow, resolve tliemselves into gaseous elements, Nitrogen is always one of these ; and thus the great regulating valve of the atmosphere onct more plays its part. SEPTIMUS PIESSE.