86 WHITTAKER-"ARTIFICIAL SILK DYEING" [March 1926

by the Worshipful Company of Dyers was delivered on 11th Jan. 1926, a t the Dyers' Hall. The Prime Warden of the comoanv

..

manholes ought to be of ample size to permit an unconscious man being drawn through them casily. Chemical works employ lead burners, plumbers, and painters, and the possibility of lead poisoning is present with them as with the workers in other branches of industry where lead compounds are used; here again the usual precautions against industrial lead poisoning must be taken."

Midgley4 deals fully with the risks and precautions in the casc of lead tetraethyl. Cdiosyncrasy pla s its part in chemical poison-

i t may also be a source of greater danger, i.c., a workcr may be practically immune to one form of poisoning but more susceptible to another. In cases of abnormal susceptibility the only thing to do is to change the operative to another class of work. Intemperance increases the susceptibility to chemical poison- ing, as to many forms of organic disease. Such rnatters are, however, the province, of the certifying doctor.

ing, but althoug il i t may be useful personally,

C. M. WHITTAKER, B.8c. (of Messrs . Courtaulds Ltd . ) .

17 See Home Olflw "Menioraiiduni 011 Iliduatrid Lead I'oison- iiig." (R.M. S t a t h r y Ofice.)

In the matter of general precautions i t is always a source of amazement to observe thc slackness regarding such elementary precautions as efficient lighting, proper drainage of floors and ya rb , and repairing of leaky roofs and walls. Elimination of ill-lit spaces and passages is important. Chemical eczema may be set UP in a worker who is wearing an unsound pair of boots and chances to step in a puddle-which in most chemical works will not be merely a p~ddlc: of water. The provision of clogs or gum boots goes far to eliminate such a risk. Leaky roofs will cause slippery floors and steps, and thus induce accidents. The provision of grids or gratings does not entirely prevent this risk. The author received a bath of molten T.N.T. through slipping on an iron checker plate floor. Moreover, the repair of a leaky roof has its direct economic side, since it prevents damage to products. Education is perhaps after 811 the best possible precaution to take against all kinds of accidents. EmplGyerR may supply all the safeguards which are humanly pos~iblc, but there can be no great progress until the worker himself, through being educated, realisex the value of "safety first."

Correspondence Staining with Azo Chrome Blacks

To the Editor of the Journal of the Society of Dyers and Golourists.

Sm-We have recently had experience of grey mixture pieces, the black component of which was dyed with Azo Chrome Blacks of the Eriochrome Black T type, turning up after finishing with a slight yellow cast on the white wool, which spoils the clear blue tone of the finished goods.

As a result of a coiisiderable amouiit of work done in this laboratory, and also on a practical scale, we have found that the fault is due to free sodium carbonate left in the goods after scwuring and milling. The fault is increased where a very greasy wool has been dyed, and the grease has not been entirely removed in thc dyeing process. Grease, however, is not, the cause of the fault, but merely an assisting factor.

The fault can be remctlictl I)y t Iiororrgh washing off after milling, preferably adding a little acid to the washing-off liquor, formic acid being the most suitable.

In cases wherc the handle of the goods may be impaired by this final treatment, the excess of acid should be again ncut,ralised with a littlc ammonia.

We should be obliged if you would publish this communication, as we consider these facts should be widely known, particularly among finishers.

We are, dear sir, yours faithfully,

For C . Hoherte C(c Co. Lttl.,

FREUERIC I,. GOODALL, M.Sc., (:/Lorn is/.

Bradford, l k c . lsth, 1925.

External Lecture The fourth of the series of lectures arranged I Artificial Silk Dyeing

A " -~

(Mr. Maurice Tidd) presided, and was accom- panied by Mr. Septimus Marshall (Renter Warden),

Four varieties of artificial silk come within the purview of the artificial silk dyer-nib- cellulose, cupramnionium, viscose, and acetate