The spring of air

In 1661, Robert Boyle presented a communication to the Royal Society describing his discovery of the relation, later known as Boyle s law, between the pressure and the volume of a given mass of air. Boyle s original data, which were pubhshed in 1662, in the second edition of his New Experiments Physio-Mechanical, Touching the Spring of Air and its Effects, are presented in Table 5A.1. We are going to fit a few pol3momial models to them and evaluate these fits by means of the ANOVA and the inspection of residual plots. 

The fits are performed in the usual manner, by least squares (Eq. (5.12)) 

All of the terms in these models are significant, as we can see from the relatively small sizes of their respective standard errors. Each additional term eliminates 1 degree of freedom from the residuals but this does not worsen the models — judging by the ANOVA results, they are progressively improving. The cubic model, for example, has MSg/MSr = 3214.15, and explains 99.78% of the total variation. With these numbers, we would hardly bother about finding a better model. When we look at the 

Experimental data from Boyle s experiments. The pressures are in atmospheres. The volume unit is arbitrary 

Changing the independent variable from U to 1/U is, for obvious reasons, an example of what is known as a linearizing transformation. This is an important lesson. Before thinking of adding new terms and complicating a model, we should always reflect if there is not some variable transformation that might produce a more satisfactory fit. In any case, the residual plot is always an excellent indication of the success of a particular model. 

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Boyle s research assistant was Robert Hooke (1635-1703), who would become a famous scientist in his own right. Together they performed a series of experiments that would transform not just the study of matter but the practice of science. Boyle was particularly interested in air, and his great tool for the study of air was the air pump. He looked at the relationship of pressure to volume, finding, for example, that water would boil at a lower temperature at low pressure. His experiments were compiled and published in New Experiments Physico-Mechanicall Touching on the Spring of Air and Its Effects (1660). It was... 

Plate eolleetors were set at two heights above the ground, whieh may give an indieation of air eoneentration gradients. The two Broadbalk plots reeeived nitrogen fertilizers in the spring of eaeh year the lawn and parkland were unfertilized. 

These and other experiments were fully described in Boyle s book New Experiments Phisico-Mechanicall, Touching the Spring of the Air, and Its Effects (Made for the Most Part in a New Pneumatical Engine), which was published in 1660 and established his reputation as a natural philosopher. Spring of the Air had a great influence on other scientists, who built their own vacuum pumps, repeated Boyle s experiments, and devised new ones of their own. Air, they now realized, was something that had very specific properties that could be experimentally investigated. 

For example, while the vortex-averaged 03 concentration at one altitude in the Arctic in the spring of 1994 was measured to decrease by 10%, the net chemical loss was estimated at 20% but this was partially compensated by an increase due to transport of air containing higher ozone concentrations from higher altitudes (Manney et al., 1995). Similar amounts of chemical ozone loss in the Arctic polar vortex have been calculated based on measurements of CIO, BrO, and 03 (e.g., Brune et al., 1991 Salawitch et al., 1993). 

It was at this point in the Spring of 1773 that Lavoisier embarked on a systematic study of the fixation and liberation of airs, a topic much pursued in other countries but The French Chemists alone seem not to take any part in these important inquiries. The results of this intensely pursued task were published in January of 1774 as Opuscules physiques et chymiques (Physical and Chemical Essays). In the first half of this book, Lavoisier thoroughly reviewed the work previously published on the topic in the second part he described his own experiments, consisting chiefly of repetitions of earlier work, though often with different observations and interpretations. Here for the first time he put into print his view of calcination and reduction of metals. 

Down to the spring of 1938 the Air Ministry had avoided placing orders for obsolescent aircraft merely to boost production figures. On 27 April 1938, however, the Cabinet, under parliamentary pressure to match German aircraft production, authorised the Air Ministry to accept as many aircraft as it could from the British aircraft industry, up to a maximum of 12,000 machines over the next two years. The Treasury readily sanctioned expendimre on plant required for the programme. As a result of these measures the gap between British and... 

The scientific publications of Boyle began in 1660 with his extensive treatise on the Spring of the Air, in which he made use of an improvement on the air pump discovered by Otto von Guericke,—his newly discovered pneumatic engine. This was a very important contribution to the physics of air, in the course of which ho announced the generalization still called Boyle s Law and sometimes called Marriott s Law, though Marriott announced it some seventeen years later. 

Robert Boyle called this resistance to compression the spring of the air. 

DEHP was detected in samples (one from a commercial site and five from residential sites) of both dust and air obtained from all sites (Rudel et al 2001). In dust, the concentration of DEHP ranged from 69.4 to 524 g/g dust, with a mean concentration of 315 g/g dust. In air, 4/6 sites had DEHP at concentrations above the minimum detection limit (MDL), ranging from 0.02 to 0.114 g/m3, with a mean concentration of 0.061 g/m3. In another study, indoor measurements ofDEHP taken in six homes in the spring of 2000 ranged from 0.04 to 0.23 g/m3 (Otake et al. 2001). In one workplace (plastic melting facility), a value of 11.5 g/m3 was measured in air (Rudel et al. 2001). 

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