Instrument Makers

Instrument makers nonetheless provide this less-than-useful information, but hardly anybody recognizes as the outflow of the wide calibration range, the linear concentration-to-signal transfer function, and the excellent repeatability. 

One of the major trends to be anticipated is greater availability of instrumentation that can be used to perform multidimensional separations at ultrahigh pressures. Some instrument makers have recently introduced LC pumps capable of operating at pressures up to 15,000 psi. As time progresses, ultrahigh pressure separations are likely to become more routine and the pressure limit of commercial instruments is likely to increase... 

Multiple sprayer ion source with rotatory ion beam chopper (MUX) (performed by instrument maker) Place two to four sprayers in same interface housing each sprayer receives effluent of HPLC spinning chopper protects orifice of MS to allow ions only from one sprayer to enter at a time special MS program separates data from sprayers HPLCs operated in parallel and simultaneously... 

Education of the Manufacturer. Raw data needs to be preserved, and, as one said, "Sometimes I emphasize to the instrument makers that today s microprocessors cannot be depended upon to stashing away raw data they can t archive it very well, there, on the instrument. Besides you are stuck with the instrument that the makers supply us...we should have better control. ... 

Fahrenheit. The temperature scale invented by the century instrument maker Daniel Garb riel Fahrenheit that has 32.2° as waters freezing point and 212° as the boiling point. (Originally Fahrenheit set the scale, thinking that 96° was normal body temperature and 32°, waters freezing temperature. Subsequently he realized that by his scale 0°F... 

Anders Celsius (1701-1744) from Sweden devised his temperature scale in 1742. Celsius assigned a value of 0 to the boiling point of water and 100 to the temperature of thawing ice. Instrument makers soon reversed the 0 and 100 to give us the modem freezing and boiling points of water as 0°C and 100°C, respectively. The relationship between the Fahrenheit and Celsius temperature scales are given by the two equations ... 

It Is seen from equation (30) that the optimum flow-rate Is also proportional to the extra column dispersion and, as a consequence, the total volume of mobile phase employed in an analysis will also depend on the extra column dispersion. It follows that the economy of the analysis lies in the hands of the designer of the chromatograph, a responsibility for which, many instrument makers are not aware. Steps taken in the design of the chromatographic system that would reduce the extra column dispersion by a factor of two would also halve the volume and cost of solvent used in the... 

For details of Molyneux s globes and further references see Gloria Clifton, Directory of British Scien tific Instrument Makers i o-i8si (1995), 191 and Peter von der Krogt, Globi Neerlandici The Production of Globes in the Low Countries (Utrecht, 1993), 107—12. 

Clifton, Gloria, Directory of British Scientific Instrument Makers iff 0—18 1 (1995). 

Elizabethan Instrument Makers The Origins of the London Trade in Precision... 

Data Analysis. The computerization of spectrometers and the concomitant digitization of spectra have caused an explosive increase in the use of advanced spectmm analysis techniques. Data analysis in infrared spectrometry is a very active research area and software producers are constandy releasing more sophisticated algorithms. Each instrument maker has adopted an independent format for spectmm files, which has created difficulties in transferring data. The Joint Committee on Atomic and Molecular Physical Data has developed a universal format for infrared spectmm files called JCAMP-DX (52). Most instrument makers incorporate in their software a routine for translating their spectmm files to JCAMP-DX format. 

The arrangement of the topics that follow continues that developed for Recent Developments in the History of Chemistry General Works, Instruments and Apparatus of Particular Chemists and Laboratories Instruments and Apparatus by Type and Function Museum and Laboratory Collections and Instrument Makers. 

A major, systematic piece of research has resulted in a directory that lists British scientific instrument makers who were active over the period 1550 to 1851.16 This has been compiled mainly from the records of the London companies and guilds. What is particularly fascinating is that it provides an insight into the family relationships of makers by revealing who was apprenticed to whom. 

No general surveys of chemical instrument makers have been published though a review of 19th-century scientific instrument-making in France has appeared.93 Perhaps more useful to those interested in instruments themselves is a series of some thirteen papers that considers firms of French scientific instrument makers, singly or in small groups.94,95 These papers draw attention to the vicissitudes of what was often a fragile industry. 

R. G. W. Anderson, J. Burnett and B. Gee, Handlist of Scientific Instrument-Makers Trade Catalogues 1600-1914, National Museums of Scotland, Edinburgh, 1990. 

P. Brenni, 19th century French scientific instrument makers I H. P. Gambey , Bull. Sci. Instrum. Soc., 1993, 38, 11-13. 

T. Lenoir and C. Lecuyer, Instrument makers and discipline builders the case of nuclear magnetic resonance , Perspectives Sci., 1995, 3, 276-345. 

T. Lenoir, C. Lecuyer, Instrument makers and discipline builders the case of nuclear magnetic resonance, Perspectives on Science 3 (1995) 276-345 F.D. Becker (ed.). Encyclopedia of Nuclear Magnetic Resonance, volume one, Historical Perspectives (Chichester Wiley, 1996) J. Feeney, Development of high resolution NMR spectroscopy as a structural tool, in Bud, Cozzens. Invisible Connections, 199-216. 

Those who engage in tooth whitening should be aware that it has a weakening effect on the enamel. This was reported at a meeting of the US Materials Research Society in Boston in November 2005 by Michelle Dickinson who works for Hysitron, an instrument maker based in Minneapolis. This company has developed a piece of equipment capable of measuring the hardness profile of teeth across the enamel and dentine... 

When Lavoisier invited the younger Laplace to collaborate with him in a quantitative study of heat, the invitation was a great compliment to the younger scientist. The results of their joint research were presented to the Royal Academy of Sciences in 1783. The collaboration was symbolic of the union of chemistry with physics and a landmark in the quantification of what Lavoisier regarded as an imponderable substance, that is, a substance without weight. Both scientists were committed to the search for precise measurements, at a time when instrument makers were producing apparatus of unprecedented accuracy. 

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