STATE GEOLOGIST, 139 
any shells or other lumps and helps to insure a homogeneous sample. About 50 or 60 
cc. are poured out thin on a hot electric griddle, where it dries in a few moments. The 
dry sample is ground fine in a mortar without sifting. 
DRYNESS. 
A small wide-mouth bottle is filled with the slurry and leveled off. About 20 ce. 
is poured into a tared pan, in which it is dried on the hot plate and then weighed. The 
bottle, without being cleaned, is filled with water from a burette, indicating the amount 
of sample taken. From this and the weight, as above, a factor is obtained with which to 
calculate the amount of material in a measuring tank. “‘Weight”’ divided by “‘burette 
reading” equals “dryness,’”’ which multiplied by the capacity of the tank in litres would 
give the number of kilos of dry material. ; 
ANALYSIS. 
0.5 g. of the sample and 5 g. sodium carbonate are mixed in a thirty cc. platinum 
erucible and fused over a blast lamp. After the charge is melted it is poured out on a 
LENGTH AcCORDING TO CAPACITY 
<= 50mm—><—— ae ene Oe pp eee Sear 
| 
LONG TAPERED SHOULDERS 
AT BOTH, ENOS 
CALIBRATION MARK 
Fig. 11. The Ludlow and Harrop marl pipette, to contain 3.37 c.c. 
clean carbon plate. With the aid of a dropper the crucible and cover are cleaned and 
rinsed with a minimum of 1 to 1 hydrochloric acid, into a No. 6 evaporating dish. The 
Jump of fused material is dropped in and about 15 seconds later 10 cc. of concentrated 
hydrochloric acid is added, the dish is covered with a watch glass and set on a water bath. 
After all effervescence has ceased and it has steamed a moment, to automatically rinse 
any spattering from the covering, the latter is removed and set aside to be used later. 
With this minimum amount of liquid the fused mass is all decomposed, but part of the 
sodium chloride and most of the silica is precipitated by the strong acid. This precip- 
itate being dense and granular stays at the bottom of the dish, and the evaporation 
proceeds more rapidly than usual, without scumming over or caking, and is finished in 
twenty to thirty minutes; when especially hurried the evaporation is hastened by 
playing on the surface of the liquid with a Bunsen flame. 
When entirely free from smell of acid the dish is removed from the water bath. 
After wetting the saline mass with hot water, 10 ce. concentrated hydrochloric acid is 
added, the sides of the dish washed down with hot water, covered with the watch glass 
and set on the hot plate to boil a moment. With the aid of the filter pump and bell jar 
the solution is filtered into a 600 ce. Griffin beaker through an 11 em. ashless filter. The 
dish is rinsed out with hot water and the filter washed twice. The funnel with the filter 
is transferred to a filtering flask, the dish cleaned out with the aid of a finger cot and 
rinsed into the filter, and the latter washed twice more. By the above procedure practi- 
cally all the soluble part of the sample is in solution, and its volume kept low. The filter 
is burned and ignited over the blast lamp, and the silica transferred from the platinum 
crucible to a tared watch glass and weighed. 
To the filtrate are added a couple of drops of strong bromine water and 20 ce. of a 
mixture of ammonia and ammonium chloride. This mixture is of such a degree of 
strength that the above amount will contain ammonia enough to neutralize the 10 ce. of 
