THE CALCARIMETER. 251 



manipulation is avoided, and that there is no calculation re- 

 quired. 



The first thing to be furnished with is an instrument which 

 consists simply of a tube about half an inch in diameter and 

 ten inches long, having the principal part of it graduated in 

 one hundred parts. The simplest form to be given to this tube 

 is such as is represented in figure 1, the extremity a being 

 drawn out and bent downward, leaving an opening so small 

 as to allow a liquid to flow but slowly from the tube. To the 

 upper part, for convenience' sake, is adapted a perforated cork, 

 with a small tube. This is placed for the purpose of regulating 

 the flow of the fluid, by placing upon it and withdrawing from 

 it the finger, as we may wish to arrest or allow the liquid to 

 flow from the extremity a. With this instrument, that I pro- 

 pose calling the Calcarimeter from its use, we must be furnished 

 with two fluids, a solution of muriatic or nitric acid and a 

 solution of ammonia, both of which are prepared of a certain 

 strength.* 



Preparation of the acid solutio?i. — This solution is prepared 

 as follows: weigh out fifty grains of dry, finely-powdered pure 

 carbonate of lime, or what is better, carbonate of lime precipi- 

 tated from any of its solutions by carbonate of potash or soda. 

 Place this in a cupsule or other convenient vessel ; add to it 

 about an ounce of water (this is done simply for the purpose 

 of moderating the action of the acid). Then take the muriatic 

 or nitric acid of commerce, dilute it with one part of water. 

 With this liquid fill the instrument to the 100 point ; then let 

 the acid fall gently upon the carbonate of lime, so as not to 

 create a too great effervescence ; and by proceeding carefully 

 with the aid of a piece of litmus-paper we can find the exact 

 point at which the carbonate of lime is all taken up by the 

 solution having an acid reaction. . When we see that nearly 

 all the lime is taken up we proceed very cautiously, by adding 

 but a- few drops of the acid at a time, and agitating the mix- 



*The capacity of the instrument from to 100 is 30 c. c. m., and the 

 length of the graduation had better be from eight to ten inches. Of course 

 this will vary with the diameter of the tube. As they are all to be of the 

 same capacity, the graduation may be made upon the tube itself, or upon a 

 piece of paper and pasted on, then varnished, first with a solution of gum 

 arabic, and afterward with copal varnish. 



