Atmospheric carbonic acid, its estimation and variaton / lecture delivered by John Robertson on Wednesday, June 8th, 1904.

  • Robertson, John.
Date:
1904
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Licence: In copyright

Credit: Atmospheric carbonic acid, its estimation and variaton / lecture delivered by John Robertson on Wednesday, June 8th, 1904. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    Ha,dfield. I-Iadfield improved the method of collection by using a dry- bottle and filling it with air by means of a bellows. Dalton's process with the modifications suggested by Hadfield is as good and even better than many of the processes described in our text-books to-day. I will ask you shortly to consider whether we in this country are not entitled to speak of Dalton's method rather than Pettenkofer's. De Saussure. Between 1810 and 1830 De Saussure, of Geneva, published the results of his work with a gravimetric method. He precipitated the Carbonic Acid in about 34 litres of air and weighed the resulting barium carbonate. By this method he showed that the mean amount of CO3 in air was about 4'03 volumes per 10,000 volumes of air. Pettenkofer. The next important and far-reaching researches in atmospheric carbonic acid were made by Pettenkofer by a method almost identical with that of John Dalton and his pupils—a dry bottle, the air forced in by means of a bellows. Lime or Baryta water used as an absorbent and any non-volatile dilute acid for titration. Angus Smith says that the use of the oxalic acid for titration is the essential of the Pettenkofer process, but obviously that is wrong for Pettenkofer himself says any non-volatile acid will do. In view of all the circumstances I now ask you whether we, in this country, should not associate Dalton's name with the bottle method of determining CO, ? Angus Smith. You have in Manchester another very interesting link in the investigation of Atmosphere Carbonic Acid, for it was here that Angus Smith did much of his work on the subject of the variation of Carbonic Acid in the air. Those who may not have read his Air and Rain will find that it contains much valuable information in regard to Carbonic Acid. Having now indicated very briefly the scope of the older work on Atmos- pheric Carbonic Acid, I will next describe some of the more recent methods and afterwards the results. Methods in Use at the Present Time. The methods may for the sake of convenience be divided into (a) those dcAnsed to secure the greatest possible accuracy irrespective of the amount of trouble involved, and (6) those designed for practicable purposes. Those of us who are engaged in practical public health Avork, and who may be required to make Carbonic Acid determinations in examining as to the efficiency of methods of ventilation should have a knowledge of the degree of