360 Anah/sis of Scioitijic Books. 



10 by weight of salt, and the solutiou occupies the bulk, of 33 J 

 parts. 



^^ Exp. 182. The solution of bodies in acids intercepted bi/mc^ 

 ckanical pressure. Put into a Florence flask some powdered 

 carbonate of lime (chalk), and pour over it some diluted sul- 

 phuric, muriatic, or nitric acid; immediate eflervescence will 

 be the consequence. Now stop the mouth of the flask with a 

 cork ; the eflervescence will instantly stop, upon the same prin- 

 ciple that fluids refuse to boil when the superincumbent pres- 

 sure is, to a certain extent, greater than usual. If the cork be 

 withdrawn, the effervescence will be resumed. Observations. — 

 The agitated motion of bodies undergoing solution does not 

 differ from ebullition ; for in both cases the fluids vaporize ; and 

 when this pressure is used the ascension of vapour must stop, 

 not having sufficient mechanical force to overcome the power 

 of the body which presses upon it." We shudder at reading 

 this experiment, as the Florence flask will certainly burst, to tlie 

 imminent hazard of the operator's eyes. Indeed, the adviser 

 of such a project should be made liable at law for the damages. 

 It reminds us of the school-boy's attempt to extinguish a cracker 

 by putting it into his breeches pocket. 



" Exp. 183. Solutio7i of tin in nitrous acid. Pour half an 

 ounce of nitrous acid, over half an ounce of granulated tin 

 (Pulvis Stanni) in a tumbler : very little action will take place, 

 owing to the inability of both substances to present to each other 

 a sufficient surface. But if an ounce of water be added, a very 

 violent commotion will ensue, during which the tin, in an oxidated 

 state, and of a yellow colour, will be seen to run up and down 

 from the bottom to the surface, whilst a great quantity of nitrous 

 gas is disengaged. This solution is the nitrite of tin." " Ob- 

 servation. The above solutions of tin, as will be seen hereafter, 

 are much used by dyers." The dyer is to be pitied, who would 

 try to make a solution of tin, in this way. In fact, the action 

 above described ruins the process, and converts the tin into an 

 insoluble peroxide, useless to the artisan. But this is not all : 

 common nitrous acid invariably acts with great violence upon 

 powdered tin, and a tyro might seriously injure himself by 

 following Mr. Mackenzie's recipe. 



Under Exp. 412, we find an encomium on the virtues of 

 *' StrathpefFer water, a very productive well, in Ross-shire, 

 Scotland ;" the district of the Clan Mackenzie. This internal 

 evidence has partly satisfied us of the identity of the author 

 whose name is on the title-page ; we once thought it merely 

 a nom de guerre. 



At Exp. 469, p. 251, we find the following sapient remarks ; 

 " It is necessary to be observed here, that chlorine, and all other 

 gases readily absorbable by water, should be received over 

 mercury, in a trough made for the purpose of containing from 



