INTRODUCTION.

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time; lie will soon observe globules of a gas, at first small,but soon becoming larger, to collect upon the surface of thefilaments, which, when they have attained a sufficient size,will quit their attachment, rise to the surface of the water,and at last lose themselves in the surrounding air. Thiswill, I think, satisfy him that a respiration of some kind iscarried on; and should he wish to ascertain the nature of thegas thus eliminated, whether it be really oxygen or not, thismay be done by procuring a considerable quantity of anyfloating species of Conferva, and placing it in a trough ofwater, over which should be put a glass jar also filled withwater, having an air-tight collar adapted to it, so disposed asto catch the gaseous globules as they ascend. As soon asthe glass jar becomes filled with the gas, let the air-tightcollar be removed and a piece of ignited phosphorus bequickly plunged into the interior of the jar, when the brilliantand dazzling combustion which will instantaneously ensuewill afford a proof conclusive of the nature of the elimination.The honour of this discovery, if it can be deemed one, for itis but the extended application of the common principle ofthe respiration of plants generally, is in this country attri-buted to Priestley; but so obvious is it that it scarcely re-quired the penetration of a mind like his for its detection:Vaucher alludes to it cursorily.

The third use of the Conferva is a moral one. Everycreated thing, rightly viewed, is capable of imparting thismoral lesson, be it the kingly lion or the spurned reptile;the beautiful and scented flower, or the more humble pro-ductions which have been engaging our attention. There isno imperfection acknowledged in nature, nor are there,strictly, degrees of comparison; everything is superlative,is best and perfect from the hands of God who made it, alikeunsurpassable and inimitable.

Then, lastly, there is the intellectual benefit derived by thosewho study this or any branch of Nature ’s works. There arethose who regard the pursuits of natural history as trivial andtending to no useful purpose; but these are but superficial ob-