ON  SOME  CEMENTS. 
459 
of  the  dry  cold  cement  and  applying  a  warm,  but  not  too*  hot 
soldering  iron,  so  as  to  soften  the  cement  on  the  crack,  then 
melt  it  on  each  side  and  cover  it  with  the  cement.  The  cement 
will  adhere  with  great  ease  to  the  lead,  and  is  far  more  manage- 
able than  any  of  our  common  solders.  A  hole  in  a  gutter  could 
be  readily  stopped  with  the  cement  and  a  piece  of  lead  of  suffi- 
cient size  to  overlap  the  hole,  say  about  one-half  of  an  inch :; 
cover  the  lead  on  both  sides  with  a  surface  of  the  cement ;  press 
it  on  the  hole ;  then  cover  the  lead  and  its  edges  with  the  cement, 
as  in  puttying  a  pane  of  glass. 
In  the  case  of  the  common  and  forcing-pump,  it  was  only 
necessary  to  have  every  part  that  leaked  quite  dry,  and  slightly 
warm,  when  a  good  coating  of  the  cement,  in  its  thick  state,  was 
applied  so  as  completely  to  cover  the  cracks  or  apertures.  The 
cement  used  in  this  instance  did  not  exceed  in  bulk  the  plumbers' 
solder  which  would  have  been  used.  The  warm  soldering  iron 
was  lastly  applied  to  fill  up  any  interstices,  and  produce  through- 
out a  uniform  surface. 
I  entertain  no  apprehension  that  the  warmth  of  our  climate 
at  any  time  will  impair  the  efficacy  of  this  cement  when  applied 
to  repair  lead,  zinc,  or  iron  gutters ;  for,  though  it  softens  at  a 
comparatively  low  temperature,  it  still  adheres  most  tenaciously 
to  metals  and  other  substances,  and  does  not  allow  water  to  pass 
through  it.  My  gutters  were  repaired  with  the  cement  before 
the  very  hot  weather  we  had  last  summer,  and  not  the  least  ap- 
pearance of  a  leak  has  been  since  observed  in  the  gutters. 
In  a  similar  way  the  cement  may  be  readily  applied  to  repair 
holes  in  tin  cans,  garden  watering-pots,  iron  or  other  metal  ves- 
sels which  are  used  only  for  cold  water.  Vessels  thus  repaired 
should  be  left  a  few  hours  before  they  are  used,  as  the  cement 
takes  some  little  time  to  set  or  harden. 
That  the  presence  of  water  does  not  interfere  with  the  action 
of  the  cement  was  shown  in  cases  where  I  put  a  large  hammer, 
also  a  seven-pound  weight,  into  hot  water,  for  a  few  minutes.  I 
then  removed  them  from  the  water,  and,  without  wiping  them, 
*  When  the  soldering  iron  is  too  hot,  and  applied  to  the  cement,  it  de- 
composes a  portion  of  it,  or  raises  it  in  a  white  vapor.  When  it  is  of  the 
proper  temperature,  which  is  about  130Q  Fahr.,  it  is  merely  softened  or 
partially  melted. 
