X SCIENCE PROGRESS. 



Others require correction; thus on page g: "Give on the three scales 

 the absolute temperature corresponding to the following 'critical tempera- 

 tures ' of various vapours and gases ". Of the eight gases named, the 

 critical temperatures of six are incorrectly stated. Although this fact 

 is of no consequence from a purely arithmetical point of view, it is 

 obviously desirable from other considerations that the temperatures 

 given should be the true ones. 



The directions which the author gives for carrying out the various 

 experiments suffer very much from over-condensation ; thus, a student 

 to whom it is necessary to say " cut a piece of clean solid phosphorus " 

 (p. ii), or " fill six small cylinders with the evolved gas over cleai' tap 

 water" (p. 38) (the italics are ours), would be at some loss to know how 

 to set about the following experiment : " Put about 10 grains of fairly 

 finely divided copper in a hard-glass tube, weigh it, and having raised 

 it to a fair red heat pass about 5 litres of air repeatedly over it. When 

 no further change occurs in the volume of the air stop the experiment 

 and allow the tube to cool, then weigh it" (p. 13). 



The book contains no illustrations, nevertheless we find such direc- 

 tions as the following : "Through the tube A B (App. 76, a) pass a 

 current . . . close the taps E and F, and into the limb B pour some 

 mercury," etc., etc. (p. 61). One seeks in vain for any explanation, but 

 what "App. 76, rt" refers to does not transpire. 



The arrangement of the subject matter is somewhat lacking in 

 method ; thus, the section headed " Studies on Combustion " is made 

 to include the following : — 



Preparation of sulphur dioxide from copper and sulphuric acid. 



Conversion of sulphurous into sulphuric acid by nitric acid. 



Formation of sulphur trioxide. 



Experiment to illustrate the manufacture of oil of vitriol. 



Preparation of nitric acid from nitre and oil of vitriol. 



Preparation of ammonia from ammonium chloride and lime. 



Misleading definitions of acids and alkalis. 



Experiments on neutralisation. 



Experiments showing heat evolved on the solution of certain sub- 

 stances in water. 



Part II. (about 120 pages) is called " Introduction to Chemical 

 Analysis". In it the author attempts to teach qualitative and quanti- 

 tative analysis simultaneously. Without discussing the doubtful wisdom 

 of this plan, it may be enough to point out that by the time a student 

 has reached the stage of testing for sodium, potassium, and ammonium 

 compounds, he will, if he has followed the course laid down in the book, 

 have made some hundreds of quantitative estimations. The sections 

 devoted to groups I. and II. a (silver, lead, mercury, bismuth, copper, 

 and cadmium) include alone upwards of fifty quantitative determina- 

 tions. Indeed, the author seems to have tried to squeeze the whole 

 science of chemical analysis into the compass of his little book ; thus, 

 in the five and a half pages given to the reactions of the negative (acid) 



