[4]Actually the same state may be occupied by two neutrons and two protons. The reason is that neutrons and protons are magnetic particles with a north and a south pole. Consequently the demand for a difference can be satisfied by having one neutron (or proton) with its north pole pointing up and another with its north pole pointing down. [5]It seems that neutrinos emitted in the company of electrons have the symmetry of a right screw; those emitted together with a positron have the symmetry of a left screw. [6]Actually the weights rarely add up to the original 238 because, as a rule, one or more neutrons are emitted which carry off some of the original mass. [7]Only a very few unlucky ones are overtaken by beta decay first. [8]She and her husband were the discoverers of two elements, rhenium and masurium. One of these exists. [9]A great portion of the energy might be lost if the neutron is quite fast. In this case the neutron can cause internal excitation of the nucleus. [10]There seems to be a good possibility that he died from a hepatitis entirely unrelated to the initial radiation exposure. [11]Half-lives of radioactive nuclei are uninfluenced by the extreme temperatures or pressures of the explosion, or by the state of motion of the particles or where they happen to be. [12]A small amount may drift down to the ground in the winds. This may get deposited on leaves and grass. [13]The last line of the table is based on our own estimates. [14]Recent evidence suggests this number is sometimes twenty-three. [15]Dubbed by its friends “Committee for Reactor Prevention.” [16]One of the authors. [17]This difference is not surprising. When we sterilize, we have to kill _all_ germs, even those which are most resistant to radiation. Furthermore small organisms may escape the radiation effects by mere chance. On the other hand a big and complicated organism will cease to function when the most sensitive among its essential tissues have been destroyed. Transcriber’s Notes —Silently corrected a few typos. —Retained publication information from the printed edition: this eBook is public-domain in the country of publication. —In the text versions only, text in italics is delimited by _underscores_.