An introduction to electricity : Joseph Priestley in six sections. I. Of Electricity in general. II. A description of the electrical machine. III. A description of the apparatus (belonging to the machine) for making electrical experiments. IV. How to know if the machine be in good order for performing the experiments, and how to put it in order if it be not. V. How to make the electrical experiments, and to preserve buildings from damage by lightning. VI. Medical electricity