ELISHA MITCHELL SCIENTIFIC SOCIETY 82 
For sizing each one hundred pounds of yarn nine pounds of 
starch and three pounds of tallow were used. The warps 
were run off the dyeing cylinders into sacks quite hot aud 
stored away. At the time mentioned these warps were stored 
away at four oclock in the afternoon. The fire was discovered 
at one the next morning. 
Enquiry elicited these facts; first fire; all materials had 
been on hand some time; same dye had been used for long 
time; no recent new purchase of dye; the mzll shut down for 
repairs immediately after the the dyeing and before the sizing of 
the warps which caught fire. 
Careful microscopic examination of the yarn showed only 
such changes in the fibre as resulted from the mechanical 
strain to which it had been subjected in the spinning and an 
even distribution of the dye. No spotted effect was observed 
such as would occur if chemicals in careless or ignorant hands 
had been placed upon the yarn intentionally or by acci- 
dent. 
The dye used is commercially called ‘‘naphthazarin L. W.” 
By analysis and investigation of the patent literature it was 
found to be a mixture of equi-molecular parts of tetrazo-di- 
phenyl, sodium salt of amido-naphthol disulphonic acid and 
dihydroxynaphihalene precipitated by and incorporating more 
or less sodium chloride. The tetrazo bodies under certain con- 
ditions, namely, acid, liberate oxides of nitrogen which may 
_ oxidize such substances as cotton. No acid was used accord- 
ing to the dyeing formula. 
Fires have frequently resulted from the oxidation of fats, 
as when old greasy rags are packed away in a warm place for 
along while. According to the ordinary method of dyeing 
as practiced in this mill the rapidity of the work does not 
give time necessary for oxidation which produces heat. In 
this case two weeks intervened and the tallow used in finish- 
ing either being on hand and exposed more or less to the 
atmosphere during a warm season permitting the oxidation 
to begin became rancid, or it was purchased rancid. ‘The 
oxidation of the fatty constituents of tallow once begun con- 
