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The horsepower of pigeons
252
CURRENT TOPICS.
[J. F. I.
Chrome Alum L i g h t Filter.--LE RoY W. McCAY (J. Am.
Chem. Soc., r923, 45, 2958) recommends an aqueous solution of chrome alum as a light filter in qualitative analysis. A solution of 3Io grams of chrome alum in one litre of water is prepared with the aid of heat, is cooled to room temperature, and filtered. Square prismatic bottles, Having a lateral edge of 4.7 cm. and a height of Io cm. from bottom to shoulder, are filled with this solution and corked. The resulting permanent filter is held upright, very close to the eye and 5 or 6 cm. from the flame. It completely absorbs the light emitted by sodium, lithium, calcium, strontium, and barium, and transmits that emitted by potassium, c~esium, and rubidium. J. S. H.
The Horsepower of Pigeons. E . HUGUENARD,A. MAGNAN and A. PLANIOL. (Comptes Rendus, Nov. 19, I923.)--Flying pigeons were made to unwind a thread wrapped around a reel. The number of revolutions were automatically recorded and on the same paper fifths of a second were marked off at the same time. From these two records the velocity of flight was determined. In addition a little Prony brake was brought into play by which the bird's pull on the thread was measured. The highest amount of work done in a second was 1.29 kilogrammeters and the least was .36. The work per second for one kilogram of the weight of pigeon ranged from 2.63 to .73 kilogrammeter. The largest of these quantities corresponds to a rate of I/3O H.P. per kilogram. As the particular bird weighed about a pound, this would be a development of one H.P. for 3° pounds weight. There is, however, no reason to assume that the pigeons were doing their best either in speed or in traction. The authors remark that "the animal manifested a certain repugnance to flying under these conditions." G.F.S. The Spectra of Sparks Formed in Liquids.
MAURICE CURIE.
(Comptes Rendus, Nov. 19, 1923.)--Sparks were made to pass through liquid bromine, melted sulphur and phosphorus and through liquid oxygen and nitrogen. In all cases a continuous spectrum was obtained. This negatives the suggestion that the presence of hydrogen in the liquid is necessary in order that a continuous spectrum be produced, for hydrogen is wanting in all the liquids used. G. F. S.
New Extension of the Spark Spectra of Tin and Zinc in the Schumann Region. MESSRS. L. and E. BLOCH. (Comptes Rendus, Nov. I9, x923.)--Improvements made on their previous methods extend the range of their spectrograph to I3OO ,~ngstroms. For the spark spectrum of tin they add forty-five lines to the number they previously reported, while seventy-three new lines for zinc are listed. G.F.S.
CURRENT TOPICS.
[J. F. I.
Chrome Alum L i g h t Filter.--LE RoY W. McCAY (J. Am.
Chem. Soc., r923, 45, 2958) recommends an aqueous solution of chrome alum as a light filter in qualitative analysis. A solution of 3Io grams of chrome alum in one litre of water is prepared with the aid of heat, is cooled to room temperature, and filtered. Square prismatic bottles, Having a lateral edge of 4.7 cm. and a height of Io cm. from bottom to shoulder, are filled with this solution and corked. The resulting permanent filter is held upright, very close to the eye and 5 or 6 cm. from the flame. It completely absorbs the light emitted by sodium, lithium, calcium, strontium, and barium, and transmits that emitted by potassium, c~esium, and rubidium. J. S. H.
The Horsepower of Pigeons. E . HUGUENARD,A. MAGNAN and A. PLANIOL. (Comptes Rendus, Nov. 19, I923.)--Flying pigeons were made to unwind a thread wrapped around a reel. The number of revolutions were automatically recorded and on the same paper fifths of a second were marked off at the same time. From these two records the velocity of flight was determined. In addition a little Prony brake was brought into play by which the bird's pull on the thread was measured. The highest amount of work done in a second was 1.29 kilogrammeters and the least was .36. The work per second for one kilogram of the weight of pigeon ranged from 2.63 to .73 kilogrammeter. The largest of these quantities corresponds to a rate of I/3O H.P. per kilogram. As the particular bird weighed about a pound, this would be a development of one H.P. for 3° pounds weight. There is, however, no reason to assume that the pigeons were doing their best either in speed or in traction. The authors remark that "the animal manifested a certain repugnance to flying under these conditions." G.F.S. The Spectra of Sparks Formed in Liquids.
MAURICE CURIE.
(Comptes Rendus, Nov. 19, 1923.)--Sparks were made to pass through liquid bromine, melted sulphur and phosphorus and through liquid oxygen and nitrogen. In all cases a continuous spectrum was obtained. This negatives the suggestion that the presence of hydrogen in the liquid is necessary in order that a continuous spectrum be produced, for hydrogen is wanting in all the liquids used. G. F. S.
New Extension of the Spark Spectra of Tin and Zinc in the Schumann Region. MESSRS. L. and E. BLOCH. (Comptes Rendus, Nov. I9, x923.)--Improvements made on their previous methods extend the range of their spectrograph to I3OO ,~ngstroms. For the spark spectrum of tin they add forty-five lines to the number they previously reported, while seventy-three new lines for zinc are listed. G.F.S.