Report on the air of Glasgow, chiefly relative to enclosed spaces and smoke / by Wm. J. Dunnachie in co-operation with the Medical Officer of Health.
- Glasgow (Scotland). Sanitary Department.
- Date:
- 1879
Licence: Public Domain Mark
Credit: Report on the air of Glasgow, chiefly relative to enclosed spaces and smoke / by Wm. J. Dunnachie in co-operation with the Medical Officer of Health. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
12/22 (page 8)
![passing 25 cubic feet of air through each series at the rate of 1— cubic feet per hour, the last two absorbers of the first series yielded, on precipitation with chloride of barium, 0'5115 grammes of carbonate of baryta, whilst 25c c’ of the original potash solution gave 0’5157 grammes carbonate of baryta. Both of these estima- tions were made by the specific gravity process, and I believe the slight excess in the latter case to be due to the separating out of a small quantity of barium chloride crystals during the time allowed for the subsidence of the precipitates, which was less protracted in the former case than the latter. I do not found this opinion upon anything observable in the latter precipitate, but from the fact that, if a sufficient length of time be given, a large quantity of barium chloride crystals will separate out, provided the amount of carbonic acid present be small. The contents of the last two absorbers of the second set were distilled, and 100c'c- of the distillate gave, with lc c- Nessler reagent, a colouration equal to that given by 0'9C c of a solution of chloride of ammonium, the strength of which was ^inny- A blank experiment (see last Report, page 6), carried out under similar conditions, gave 0'9CC- as a reading, showing that the impurity in the first case was not due to the air passed. The contents of the last two absorbers of the third series were tested for sulphur, and gave a coloura- tion equal to that produced by 0-8cc- of a solution of bichromate of potash, the strength of which was . A blank experiment gave the same result. (For a full account of this process see last Report, page G.) Thus, the point has at length been reached when the results obtained by this method of air washing can be made available, not only for trustworthy comparison with each other, but also with those obtained by other methods. The cost of carrying out continuous observations has also been reduced to a minimum, as the washing and regulating of the air are both conducted automatically. Furthermore, by the use of Borradaile’s Patent Regulator, the variations produced by the internal economy of the meters, to which I have already referred, have been overcome, as an excess of water pressure over that absolutely required to produce the flow of air through the various solutions can with perfect safety be maintained. To ensure accuracy in the records of the meters, I have arranged to have them tested once per month, and adjusted when necessary, and, lastly, though the washing is perfected by passing the air through four absoi’bers at the rate of 1 cubic feet per hour, six absorbers will, for the future, constitute a series, so as to preclude the possibility of error. The only change in the analytical department of the investigation which I have found it necessary to make is the disuse of copper retorts for the distillation of the ammonias, and the substitution of glass ones. It was impossible to tell when the copper retorts were clean, and hence the liability to error from this source was great. In note 4, at the end of the July, August, September, and October reports, Mr. Dixon says :—“ An examination of the fluctuations presented in the foregoing Tables .... shows, amongst other things, that a rise in the nitrogenous matters contained in the air takes place during the summer months.” In view of this statement, Dr. Russell has prepared diagrams [see Plate] showing the monthly varia- tions in the quantities of ammonia, albuminoid ammonia, and sulphur in combination, as presented by the Tables for the entire year ending April, 1878. These show that whilst there is an increase in the summer, there is another, and sometimes greater, increase in the winter months. The results, it is true, were obtained by a process which, as I have proved, was far from accurate, but yet, taking them en masse over the year, their general indications may be trusted, especially as these agree with the observations of others. Thus, I find the following in page 237 of Dr. Angus Smith’s laborious work on air and rain :— “ M. Bineau has found as an average— In Winter, 16*3 milligrammes of ammonia per litre (rain). In Spring, 12T „ „ „ „ In Summer, 3*1 „ „ ,, „ In Autumn, 40 „ ,, „ ,, These observations were made at Lyons Observatory. Let us suppose for one moment that the great bulk of the ammoniacal salts found in the atmosphere of towns is the product of the spontaneous decomposition of organic matter; it would follow from Bineau’s average and the diagram that the cold of winter is much more favourable to organic decomposition than the heat of summer. If Bineau’s averages and the diagrams show anything, it is that there is another and more prolific source of ammonia than the spontaneous oxidation of organic substances. What then is this more abundant](https://iiif.wellcomecollection.org/image/b22324987_0014.jp2/full/800%2C/0/default.jpg)
