P OP ULAR MIS CELL AX Y 



429 



in the ruins and near the idol, some of which 

 were comparatively fresh, are supposed to 

 have been made and brought by them ; and 

 the suggestion is offered that it is the fact of 

 these Indians still holding in reverence the 

 temples built by their ancestors and offer- 

 ing incense in them that has led to the cur- 

 rent Central American belief in the exist- 

 ence of one of the ancient cities still exist- 

 ing hidden somewhere in the forest. The 

 mythic city has been gradually driven far- 

 ther back, and this river, the Usumacinta, 

 now marks about the last place where it 

 could be looked for. 



Lightiiing-Rods.- 



senting 



A committee, repre- 

 several societies interested in the 

 subject, which was appointed some time ago 

 to inquire into the best method of con- 

 structing and adjusting lightning-rods, has 

 recently made a most valuable report, based 

 upon all the information it was possible to 

 procure. Inasmuch as sharp points, even if 

 made of platinum, are liable to be melted 

 and blunted, the report recommends that 

 the rod should preserve its full diameter 

 nearly to the extremity, and be merely bev- 

 eled off. To preserve the sharp points for 

 drawing off the silent discharges of elec- 

 tricity, the attachment of a copper ring, 

 bearing three or four needles of suitable 

 size, at a distance of about a foot below 

 the extreme top of the rod, is suggested. 

 Vanes, finials, and other ornamental iron- 

 work on the upper part of a building, must 

 be metallically connected with the conduct- 

 or. A coronal, consisting of a copper band, 

 with stout copper points, each a foot long, 

 at intervals of two or three feet on its cir- 

 cumference, is recommended for the chim- 

 neys of factories. Copper is preferred to 

 iron as the material for rods, chiefly because 

 it is less liable to be injured and rendered 

 inefficient by rust. The diameter should be 

 three eighths of an inch for copper rods, half 

 an inch for copper rope, and nine tenths of 

 an inch for iron rods. The rods should not 

 be insulated from the building, but should 

 be attached to it by fastenings of the same 

 metal as the rod itself. A good earth-con- 

 nection is specially important. In towns, 

 connection with the iron water and gas 

 mains is recommended, but not with lead 

 pipes, because they are too liable to be 



melted. As a general rule, the lower end 

 of the conductor should be soldered to a 

 plate of the same metal as itself, having an 

 area of not less than a square yard, while 

 the hole in which this plate is sunk must be 

 so deep that the earth surrounding the plate 

 shall be moist even in the driest weather. 

 Drains and water-courses may be utilized 

 for keeping the plate in connection with a 

 large extent of moist earth. It is recom- 

 mended that the height of the rod be such 

 that a cone having its vertex at the upper 

 terminal, and its sides sloping at forty-five 

 degrees, shall inclose the whole building, or 

 as much of it as this particular rod is re- 

 quired to protect. 



Too Long School-Sessions. A govern- 

 mental commission in Alsace-Lorraine for 

 the investigation of the sanitary conditions 

 of school-life has made a report in which, 

 besides noticing the unfavorable conditions 

 that usually receive attention in such docu- 

 ments, stress is laid upon the fact that the 

 principles of mental education have not par- 

 taken during late years of the progressive 

 improvement which has characterized most 

 branches of knowledge. Thus, the greater 

 variety in the instruction which is imparted 

 by modern education fails in many cases to 

 accomplish its purpose, and is of advantage 

 only to pupils of more than average capa- 

 city. Much evil is believed to arise from 

 school - children remaining too lonff in a 

 cramped or otherwise restrained position, 

 and from the excessive and premature strain 

 to which the youthful brain is often sub- 

 jected, while the dangers of moral and physi- 

 cal infection are always present. Improve- 

 ments in the ventilation and sanitary ar- 

 rangements of schools, however important 

 in themselves, are, it is urged, of compara- 

 tively little use, when the pupil is kept for 

 too long a time every day in a combined 

 state of bodily inactivity and mental tension. 



Schools and Infectious Diseases. The 



question is sometimes presented whether it 

 is expedient to close a school, among some 

 of the pupils of which infectious diseases 

 have appeared. The fact that the condi- 

 tions and customs of school associations give 

 facilities for the dissemination of contagion 

 which are quite unknown in any other phase 



