Hundred-weight, [226]
Hydrometer, [217], [237], [238], [239]
Hygroscope, [239]
I
Ice, [100], [101], [102], [103], [104], [166], [219]
Iceless refrigerator, [105], [106]
Incubator, [196], [201], [235]
adjustment of, [199]
Ignition of gas, [140], [214], [215]
Illumination, [28], [77], [78], [82], [84], [85], [88], [218], [219]