NEGRETTI AND ZAMBRA, HOLBORN YJADUCT, E.G., 



The apparatus described afc No. 155 was used by Mr. Dewar and Dr. 

 McKendrick in carrying out some experimental research on the Physiological 

 Action of Ozone, the results being communicated by them to the Royal Society 

 of Edinburgh. In their paper the authors point out that little was known 

 regarding the action of Ozone, except its peculiar smell and the irritating effect 

 it had on the mucous membrane of the respiratory tract. Schonbein had shown 

 that a mouse died in five minutes in an atmosphere highly charged with Ozone ; 

 and it was this distinguished investigator who asserted that there was a relation 

 between the quantity of Ozone in the air and the prevalence of epidemic diseases. 



The result of Messrs. Dewar and McKendrick's experiment was, that a 

 full grown, healthy mouse lived nineteen minutes after the introduction of 

 ozone into the confining vessel, and that in ozonised oxygen, instead of dying 

 at the end of fifteen or twenty minutes, (as happened to mice in ozonised air), 

 they lived for forty or sixty minutes. 



In concluding the paper the authors stated that it would be premature, at 

 this stage of the inquiry (which opened up many points of interest in the 

 physiology of respiration), to generalise between physiological action and the 

 physical and chemical properties of ozone. Series of researches are still being 

 prosecuted () on the action of smaller percentages of ozone ; (&) on the action 

 of ozone on noxious gases and effluvia ; and (c) on any therapeutical or hygienic 

 influences it may have on the origin and treatment of zymotic diseases. 



156. Dr. Moffatt's Ozonometer consists of strips of paper prepared with 

 Iodide of Potassium and Starch ; these papers are suspended in a box so as to be 

 exposed to the free access of air, protected from the direct rays of the sun and also 

 from rain. The paper when affected by Ozone is tinged with various shades 

 of brown, the intensity of which is measured by a scale of ten gradations 

 furnished with the test papers. 



157. Negretti and Zambra's Ozonometer. These tests are now prepared 

 on a nevv formula, by which uniformity in the indications is secured together 

 with great sensitiveness and keeping qualities. 



In Tin Boxes sufficient for 12 months' observations, with Colour scale and 



full instructions for use Price, 8s. 6d. 



158. Schonbein's Ozone Tests Price, 6s. 6d. 



159. Ozone Box, constructed of painted deal on the plan recommended by 

 Dr. Moffatt. Price, 110 



160. Sir James Clarke's Ozone Case (fig. 119), consists of two cylinders 

 of very fine wire gauze, one fitting into the other ; the wire gauze being of such 

 a fineness as to permit the free ingress of air, at the same time that it shuts out 

 all light that would act injuriously on the test paper, which is suspended by a 

 clip or hook attached to the upper part of the inner cylinder. Price, 18 



Ditto in Copper 150 



161. Lowe's Ozone Case, Spiral form, japanned zinc. Price, 18 6 



