12 BULLETIN 283, U. S. DEPARTMENT OF AGRICULTURE. 
that the lead, lead oxide, or lead sulphate had something to do with 
the very efficient yield of acid obtained when using the lead spiral. 
Accordingly, a glass coil of the same length and internal diameter was 
substituted in the experiments shown in Table III. 
TaBLe III.—Sulphur dioxide oxidized to sulphuric acid in apparatus shown in figure 1. 
Glass spiral used and steady stream of oxides of nitrogen furnished. 
{ | 
| SOz2 oxidized in 
i system. : so 
pee Rate per | SOs lost 2 
Number of run. | Time of | hour of in estan 
pret e- SO> | | svstem. | omLend 
= Tn vessel | Tm glass 2 4) 7 Of Spirals 
A. | spiral B. | 
pe Pt et os PET St sy 2 Ove Selig sa ! 
| } | 
Hours. | Grams. | Per cent. | Per cent. | Per cent 
7] Ee ala an ae area gi a aie tae 13} 3.8311 147 Aes 3.15 7.34 
194s ett oe A oer Ty ors Capel rye 13 | 4.6404 43.99 59.18 } 3.20 2.63 
[En le 8 We ee ria een i tect ae: 2 5. 7888 20.18} 71.66 | 1.26 6.28 
Table IIT shows that the yield of acid was not so great with a glass 
as it was with a lead spiral. In no imstance was the gas run through 
the apparatus so fast as in the experiments in Table I], yet even 
though the oxides of nitrogen were present in large quantities in the 
gaseous mixture there was a loss of sulphur dioxide from the end of 
the spiral. . 
In order to try out the catalytic action of the lead coil, several runs 
were made with both the glass and lead spirals, but using no oxides of 
nitrogen. The results of these experiments are shown in Tables IV 
and V. 
TasLe [VY .—Sulphur dioxide oxidized to sulphuric acid in apparatus shown in figure 1. 
Lead spiral used, but no oxides of nitrogen employed. 
(In vessel | In spiral system.t | OF spiral. 
| 
| | SOs oxidized in 
f system. a SO; 
. Rate per S$O2 lost = 
a pee Auta tss/3) | (pee = escaping 
Number of run. run. | eas i i , |fromend 
[ieee 
| 
Hours. | Grams. | Per cent. Per cent. | Per cent. | Per cent. 
7A ee ae eee a eS Sea 2 1 3. 26 a" 0. 40 38508 [oe =e 61.52 
FG et ee nee See ee 1 3. 8459 
Epo Hees <)> Spaeae 
| | 
1 Could not be determined. Included in figures in column & 
Taste V.—Sulphur dioxide oxidized to sulphuric acid in apparatus shown in figure1. 
Glass spiral used, but no oxides of nitrogen employed. 
| | SOz oxidized in 
| system. so 
on 5 Rate per | SOz lost 2 
Number of run. ips of | “hour o ; in Seece 
; SOz system. | of spiral 
 — 
Per cenit. | Per cent. 
210.02 89. 23 
212.36 86. 56 
Hours. | Grams. | Per cent. | Per cent. 
Oye ee Se SS ee ee a eee 10 2. 6713 @) 0.75 
Se ee an el Sak ee et re eee 10 2. 8393 0. 40 | 0. 68 
1 Included in next column. 
2 The large loss of sulphur dioxide in the system was due in part to the renewal of the sulphurie acid in 
the wash bottle through which the gas was allowed to bubble before entering the system. This acid was 
not entirely saturated with SO, before these experiments were undertaken. 
