95 
range ol accuracy ; lifty-five out of file eiglity-one have 
weighed within 5 grains either way of the prescribed 
amount; whilst the remaining twenty-six have made greater 
errors. For the zinc sulphate lotion, one druggist out 
of the eighty-one gave the exact weight prescribed ; nine- 
teen out of the eighty-one have come within the practical 
range of accuracy; fifty-one out of the eighty-one have 
weighed within 2 grains either way of the prescribed 
amount; whilst the remaining thirty have made greateiy 
errors. 
In the actual measuring of the fiuids, I have assumed that 
measurements within 5 fluid grains either way are absolutely 
correct, whilst those within 15 grains either way are prac 
tically correct. 
For the potassium iodide mixture, six dispensers out of the 
eighty-one have measured correctly; eleven out of the 
eighty-one have come within the range of practical accur- 
acy ; thirty- two have measured within 50 grains (a tea- 
spoonful) of the prescribed amount; whilst the remaining 
forty-nine have made greater inaccuracies. For the zinc 
sulphate lotion, six dispensers out of the eighty-one have 
measured correctly ; sixteen have measured vfithin the range 
of practical accuracy; twenty-eight have measured within 25 
grains of the prescribed amount ; whilst the remaining fifty- 
three have made greater inaccuracies. Lastly, with respect to 
the strength of the solution, some dispensers may make both 
their weighings and measurements in excess or deficiency, 
and in either case the strength might be exactly what is 
required ; whilst others may have weighed correctly and 
measured incorrectly, or vice versa, and in these instances, 
the strength of the solution, which is the most important 
point, would be wrong. The following shows the amount ol 
deviation made in this respect : 
