166 



DEFINITION OF TERMS. 



grains of indigo. The following are the I tarous acids, in water, may be ap 



qualities of this ink. 



1st. It is formed of cheap materials. 



2d. It is easily made, ihe coloring 

 matter readily incorporating with the ve- 

 hicle. 



3d. Its color is good. 



4th. It flows freely from the pen. 



5th. It dries quickly 



plied to the most delicate fabrics without 

 any danger of injuring them, and the 

 same solutions will discharge writing, 

 but not printing ink. Hence they may 

 be employed in cleaning books which 

 have been defaced by writing on the 

 margin without impairing the text. Le- 

 mon juice, and the juice of sorrel, will 



6th. When dry it is not removable by also remove ink stains, but not so easily 



friction 



7th. It not aflected by soaking in 

 water. 



8lh. Slips of paper witten on by this 

 ink have remained immersed in solutions 

 of chemical agents, capable of immediate- 

 ly effacing or impairing common ink, 

 for seventy-two hours, without change, 

 unless the solutions be so concentrated 

 as to injure the texture of the paper. 

 The author offers this composition as- a 

 writing ink, to be used on paper, for the 

 drawing out of bills, deeds, wills, or 

 wherever it is important to prevent the 

 alteration of sums, or signatures, as 

 well as for handing down to posterity, 

 public records in a less perishable mate- 

 rial than common writing ink. He con- 

 cludes his paper by stating, that should 

 it be found to present an obstacle to the 

 commission of crime; should it even in a 

 single instance, prevent the perpetration 

 of an offence so injurious to society, as 

 the falsification of a public or private 

 document, the author will rejoice in the 

 publication of his discovery, and consider 

 that his labor has not been in vain. 



Edln. New. Phil. Journ. 



To make India Ink, see page 6 



as tiic concrete juice of lemons or citric 

 acid. 



Inolithus, in mineralogy, a stone con- 

 sisting of carbonate of lime, carbonic acid 

 gas, and a little iron; entirely soluble in 

 nitric acid, with effervescence. 



Inscribe, in geometry. A figure is 

 said to be inscribed in another, when all 

 its angles touch the sides or planes of the 

 other figure. 



Insolation, in chemistry, a term made 

 use of to denote an exposure to the sun, 

 to promote the chemical action of one 

 substance upon another. 



Insf.ruments, {viathematical.) A 

 pocket case of mathematical instruments 

 contains the following particulars, viz: 1, 

 A pair of plain compasses — 2, A pair of 

 drawing compasses, with its several parts 

 — 3, A drawing-pen and pointer — 4, A 

 protractor, in form of a sernicircle, or 

 sometimes of a parallelogram — 5, A pa- 

 rallel ruler — 6, A plain scale — 7, A sec- 

 tor, besides the black-lead pencil for 

 drawing lines. 



Insurance, is a contract whereby, for 

 a stipiilated consideration, called a pre- 

 mium, one party undertakes to indem- 

 nify another against certain risks. The 



To make Lithographic Ink, see page party undertaking to make the indemnity 

 15. I is called the insurer or underwriter, and 



Ink, removing the stains of. — The; the one to be indemnified the a^^'wr^'c^ or 

 stains of ink on cloth, paper, or wooA insured. The instrument, by which the 

 may be removed by almost all acids; but contract is made, is denominated a policy. 



those acids are to be preferred which are 

 least likely to injure the texture of the 

 stained substance. The muriatic acid, 

 diluted with five or six times its weight 

 of water, may be applied to the spot, and, 



Integer, in arithmetic, a whole num- 

 ber in contradistinction to a fraction. 



Internal, \n general, signifies whatever 

 is within a thing. 



Euclid proves that the sum of the three 



after a minute or two, may be washed angles of every triangle is equal to two 

 off, repeating the application as often as i I'ight angles; whence he deduces several 

 may be found necessary. But the vege-' useful corollaries. He likewise adduces 

 table acids are attended with less risk, j from the same proposition this theorem, 

 and are equally effectual. A solution of j viz: that the sum of the angles of every 

 the oxalic, citric (acid of lemons) or tar- 1 rectilinear figure is equal to twice as 



