SCIENTIFIC LITERATURE. 



315 



SCIENTIFIC LITEEATURE. 



A HISTORY OF THE THER- 

 MOMETER. 

 Dr. H. Cakrikgto^t Bolton is one of 

 the few Americans acquainted with the 

 history of science, and his little volume 

 on the evolution of the thermometer 

 (The Chemical Publishing Company) 

 represents a type of publication too 

 rare in this country. The scientific in- 

 formation is correct throughout and is 

 based on first hand knowledge, while at 

 the same time the contents are suSi- 

 ciently interesting to be read by any 

 one. It is probably not generally 

 known that the thermometer was in- 

 vented by Galileo. When we remember 

 that we owe to this one man not only 

 the foundations of physical science, but 

 also in large measure the pendulum, the 

 compass, the telescope and the micro- 

 scope, it may lead to a certain amount 

 of modesty in our appreciation of mod- 

 ern inventions. Galileo, probably in 

 1595, invented the open air ther- 

 moscope; he determined the relative 

 temperature at different places and at 

 different seasons of the year and made 

 experiments on freezing mixtures. In 

 1611 Sanctorius applied Galileo's in- 

 strument to the diagnosis of fevers. 

 Ferdinand II. of Tuscany, to whom we 

 owe the famous 'Accademia del 

 Cimento,' first sealed the glass, making 

 the instrument independent of atmos- 

 pheric pressure. Many improvements 

 were gradually made especially in the 

 endeavor to find fixed points on a defi- 

 nite scale, the freezing point of water 

 being first used by Robert Hooke in 

 1664. Of the three thermometers still 

 in use, Fahrenheit's thermometer was 

 invented in 1709, Reaumur's instru- 

 ment in 1730 and the scale of Celsius in 

 1742. None of these thermometers, 

 however, are now used in the form in 



which they were originally devised, and 

 Dr. Bolton calls attention to the some- 

 what curious fact that the instrument 

 constructed by the German, Fahrenheit, 

 is used almost exclusively by English- 

 speaking peoples; that invented by the 

 Frenchman, Reaumur, is used chiefly in 

 the north of Europe, while that of the 

 Swede, Celsius, is used in the French- 

 speaking countries. Dr. Bolton does 

 not attempt to compare the useful- 

 ness of the three scales. The centi- 

 grade scale is, of course, the most 

 logical, but, as sometimes happens 

 in this world, it is not quite cer- 

 tain that it is the most convenient. 

 When the scale of temperature between 

 freezing and boiling water is divided 

 into one hundred parts, the degrees 

 seem to be somewhat too large for use 

 in daily life, whereas if it were divided 

 into one thousand parts they would be 

 obviously too small. It is possible, how- 

 ever, that this is Anglo-Saxon preju- 

 dice, and that the centigrade degree 

 measures temperature with sufficient 

 accuracy for ordinary purposes, while 

 its decimal subdivision must certainly 

 be used hereafter for scientific work. 

 Dr. Bolton's book is so small that it 

 seems a pity that he did not add a 

 chapter on the exact thermometric 

 methods of the nineteenth century. 



EXPERIMENTAL PSYCHOLOGY. 



Professor E. B. Titchener, of Cor- 

 nell University, has given us our first 

 adequate laboratory manual of experi- 

 mental psychology and has thus marked 

 an epoch in the development of a 

 science. Experiment in psychology, like 

 much else, goes back to Aristotle, and 

 has never since been entirely lacking. 

 The great philosophers — ^Descartes, 

 Hobbs, Kant and the rest — advanced 



