EECEEATIVE SCIENCE. 



333 



time, man, a spiritual spring of knowledge, 

 attains a kigher and a higher elevation as 

 increase of wisdom enhances the force of his 

 mental impulses. 



That the earth has cooled since the days 

 when the igneous rocks first assumed a solid 

 form is certain, else it could never have been 

 peopled with its present congress of created 

 creatures ; but that it should ever cool so far 

 as to become a frozen mass is matter of con- 

 jecture. Eespecting the past, we have phy- 

 sical evidences and written records ; respect- 

 ing the future, we have only the word of 

 Revelation, and that is all we need for an 

 assurance that the earth wiU not pass into 

 frigidity, but have an end of its present days 

 through the same physical influences which 

 have given it its present geographical con- 

 figuration. 



Theology is not the province of this 

 work, else we would apply this theory of 

 the internal heat of the earth to the illustra- 

 tion of those passages in Holy Writ which 



proclaim that the earth shall terminate her 

 history in fire, " in the which the heavens 

 shall pass away with a great noise, and the 

 earth also, and the works that are therein 

 shall be burned up." The source of the 

 combustion is beneath our feet ; we tread on 

 the roof of the blast furnace, which is ready 

 to let loose the devouring flame, when God 

 wUls the dissolution of the system of being 

 into which He hath breathed the breath of 

 life. This is one more " Testimony of the 

 Eocks " to the truths set forth in revealed 

 religion. If we do not follow this branch of 

 the subject into detail, we must nevertheless 

 accept the lesson drawn from it by the 

 apostle — " Seeing that all these things shall 

 be dissolved, what manner of persons ought 

 ye to be in all holy conversation and godliness ; 

 looking for and hasting unto the coming of 

 the day of God, wherein the heavens being 

 on fire shall be dissolved, and the elements 

 shall melt with fervent heat." 



Shielet Hibbeed. 



ROBERT'S TEST-LINES. 



"How much does my microscope magnify, 

 with its various powers?" is a question of in- 

 terest to all who purchase or use one of these 

 instruments. The beginner is mostly pleased 

 with the number of times he can magnify an 

 object ; those who have become habituated to 

 the instrument by long practice regard this 

 as a very small consideration, and look to how 

 much of structvire can be shown by the least 

 amount of enlargement. But there are cases 

 where this latter quality is as such essential ; 

 forif wehave objects sosmallas torequirehigh 

 powers to show them as a whole, and these 

 composed of a great number of still finer parts, 

 it is obvious that very high powers must be 

 used for observations on their minute details. 

 Standards by which to estimate the magnify- 

 ing powers of glasses by difierent makers have 



been found in the scales of moths, amongst 

 which those of the common clothes-moth, 

 from their minute size and the regularity of 

 their markings, have been held in high esti- 

 mation. As in course of time glasses were 

 made of greater power, other " test-objects " 

 were sought for, and the scales of Lepisma, 

 and afterwards of Podura, came to be used ; 

 these being replaced by certain of the Diato- 

 macese, on the discovery of the exquisite 

 delicacy of the sculpturing on many of their 

 valves. Many an enthusiastic microscopist 

 is yet to be found who regards the successful 

 resolution of the strise on some difficult dia- 

 tom as a great triumph, worthy the bestowal 

 of time and patience without end. But a 

 difficulty occurs with all natural objects, that 

 no two are alike ; some, of the same kind 



