64 CHEMICAL DEPARTMENT. 



Some inconvenience having been experienced by persons 

 sending samples for Analysis which had not been selected with 

 sufficient care, and were afterwards found not to represent the 

 average composition of the substance, it is particularly requested 

 that the following instructions may be attended to as closely as 

 circumstances will permit. 



INSTRUCTIONS FOR SELECTING SAMPLES FOR ANALYSIS. 



Manures. — A large double handful of the Manure should be 

 taken from each of at least five or six different bags ; and if any 

 lumps are found in it, a due proportion of these should also be 

 taken. The whole being laid on a large sheet of paper, should 

 be carefully mixed by rubbing with the hand, the lumps being 

 broken down and mixed as uniformly as possible with the 

 powdery part. If this mixture be carefully made, a quantity of 

 it not exceeding two ounces will suffice for the analysis. It 

 should be folded up in tinfoil to prevent its becoming dry. In 

 default of tinfoil, the sample may be wrapped in double folds of 

 strong writing paper. Should the manure contain stones, or be 

 very moist, or should any difficulty be experienced in making a 

 uniform mixture, it is desirable that two or three pounds should 

 be sent. 



Soils. — In selecting Soils for analysis, five or six spadefuls 

 should be taken from different parts of the field, and after being 

 spread out in a thin layer for several days to dry, should be put 

 two or three times through a fine sieve, so as to insure uniform 

 mixture. For a complete analysis, not less than two pounds 

 should be sent ; for a partial analysis, three or four ounces will 

 be sufficient. 



Waters. — For the complete analysis of a Water, from two to 

 three gallons are required ; for the determination of the amount 

 of salts in solution, and lime thrown down by boiling, two quarts 

 will suffice, A well water may be selected at any time ; but the 

 water of a spring or running stream should be taken in dry wea- 

 ther. The jars or bottles in which they are sent must be tightly 

 corked and sealed. In the analysis of a mineral water, it may 

 sometimes be desirable to determine the amount of gases held in 

 solution; in which case certain precautions must be observed 

 which require the presence of a chemist at the spring. 



Limestones, Clays, Ironstones, &c. — If the bed of any of these 

 substances of which the analysis is required be very uniform in 

 appearance, a piece of two or three ounces' weight taken from any 

 part of it will be enough for analysis ; but in all cases, it is better 

 to send three or four chips from different parts of its thickness. 

 Sometimes where the characters of different parts of the bed vary 

 much, separate analysis of these portions may be requisite, in 

 which case two ounces of each may be sent. 



