NOTES AND NEWS
SCIENCE. mend it. It appeals to ' true amateurs,'boys who have a scientific turn of mind, and men who have some leisure from their work, but who have not the facilities that a laboratory offers. The tools requiredl are of the simplest kind, no turning-lathe or expensive apparatus being needed. Most of them are to be found in the ordinary equipment of a householder: the rest may be purchased for a few dollars. The materials, too, are iniexpensiv-e and easy to get. The (lirections in this book
... ons in this book are full and clear, and where it is necessary dimensional drawings are given. When the amateur has built every thing that is described, he will find himself in possession of quite a complete set of apparatus for electrical experiments,galvanometers, electroscope, condenser, vxoltrmeter, \Vinmhurst machine, induction-coil, etc.; andl, if hie compares the cost of them with the catalogue prices, he will have cause to conigratulate himself. But the miost important thing he has acquiredi is a skill in manipulation, and a knowledge of the instruments that will enable him to experimenit usefully with them. There are soime verhal errors in the book, -we do not usually speak of " 8 houzrs' resistance," for example, -but they (to not take away its usefulness. In that part of the appendlix, however, that treats of accumulators, there is the serious nmistake of confusinlg discharge-rate with storage-capacity. Page I74 had better be onitted.