282 Scientific Intelligence, 
grms. NaO CO, c. c. SO, 
Pe aR Hts ME TTBS ed inion, 
I. 04177: 0°53 :: 41°88 : 63°14 
II. 0°4126:0°53 :: 41°39: 53°17 
Accordingly 0°53. grm. NaO CO, neutralize 53:155 ¢ SeiPgs 
If the solutions are employed for nitrogen po ae earn how 
much nitrogen corresponds to 1 ¢.¢. of acid, by the following ae 
c.c. SO, grm., N. 
ee c - es ¥ 
53°155: 1° :: 0°140 : 0°0026338 
nay then write on the label of the acid bottle the following data 
for calculation. 
lec KO are OS ORAD:&: c..BO,. 
Lo. ti Sle 64 cc. KO. 
1 ¢.¢ so; re sigs grm. N, 
As an example of the determination of nitrogen by help of these so 
~~ the following mare is of ene acid made by Mr. Peter Col- 
lier in this La ere ay be adduc 
0:3923 rms. hippuric acid were Gea with soda-lime and the am- 
moniacal products were colteatad in 20 e.c. of the standard acid con- 
tained in the usually employed bulb tube. When the combustion was 
complete, the contents of the bulbs were rinsed out into a flask, brought 
to the volume of 150 c.c. and, after adding 10 drops of cockisiiil the 
— mete was eh ae in, until the change of color indicated neu- 
tralization; 13°7 c.c. of KO were required, = 8354 ¢.c. SO, (1 13°7X 
060976) hich sortie from 20 ¢.¢. left 11°646 SO, as equivalent to 
the pice of the hippuric acid. 11°6460-0026338 = pape 
: = 7818 per cent. The calculated per centage i | 
The aibinhade of scahinenl over litmus as an indicator, are as oectie 
. It possesses far greater sensibility. Luckow asserts that water whi of 
is is tinged faintly orange by it, becomes distinctly red by te addition 
zoo;cooth of ammonia or y.¢34$,09th of carbonate of lim in 
When a little pulverized marble is covered with the ailuted tincture 
allowed to stand for some time, the lower stratum of — ee 2c 
carmine tinge and by shaking, the whole solution becomes red. Lu ckow 
considers that in this case the carminic acid attacks the marble and ene 
a lime salt which causes the change of color. In this way the minu 
traces of carbonates of alkali-earths may be detected in pulverized mi 
erals, clays, &e. Alkali-salts meats cts course be removed by washing 
with distilled water free from tions 
This extreme (neers allows of aa use of much more dilute solu 
~ can be employed with litmus. wd 
2. According to ‘Luckow, cochineal is quite cog to carbonic lanl 
sulphydric a cids, carmin acid bein ng stronger than these. This is Pi for 
cally true for solutions of par strength. Hence a normal alkali i 
technical analysis may be prepared by simply dissolving a wet weigh: ey 
of carbonate a ina known volume of water, a from this AK ‘ 
dard acid may be easily made. In the neutralization it is not ae 
pil carbonic acid by boiling. The influence of the latter is er ele 
once seen when a caustic and carbonated alkali are operated with 
